5962-8957701QXA - Aeroflex UTMC

BCRTM-1

UT1553 BCRTM

FEATURES

pComprehensive MIL-STD-1553 dual-redundant Bus

Controller (BC) and Remote Terminal (RT) and

Monitor (M) functions

pMIL-STD-1773 compatible

pMultiple message processing capability in BC

pTime tagging and message logging in RT and M modes

pAutomatic polling and intermessage delay in

BC mode

pProgrammable interrupt scheme and internally

generated interrupt history list

pRegister-oriented architecture to enhance

programmability

pDMA memory interface with 64K addressability

pInternal self-test

pRadiation-hardened option available for 84-lead

flatpack package only

pRemote terminal operations in ASD/ENASD-certified

(SEAFAC)

pAvailable in 84-pin pingrid array, 84-lead flatpack, 84-

lead leadless chip-carrier

pStandard Microcircuit Drawing 5962-89577 available

- QML Q and V compliant

CONTROL

DMA/CPU

MESSAGE

RT/MONITOR

MESSAGE

BC PROTOCOL

HANDLER

INTERRUPT

CONVER-

PARALLEL

SERIAL-TO-

CONVER-

TO-SERIAL

PARALLEL-

MODULE

DECODER

ENCODER/

CHANNEL

DUAL

BUS

TRANSFER

LOGIC

ADDRESS

TIMEOUT

TIMERON

CLOCK &

RESET

12MHz MASTER

RESET

GENERATOR

ADDRESS

1553

HIGH-PRIORITY

RT ADDRESS

STANDARD INTERRUPT

HIGH-PRIORITY

INTERRUPT LOG

CURRENT COMMAND

BUILT-IN-TEST WORD

POLLING COMPARE

CURRENT BC (or M) BLOCK/

STATUS

CONTROL

REGISTERS

LIST POINTER

DATA

BUILT-

IN-

TEST

MONITOR ADDRESS

INTERRUPT STATUS

INTERRUPT ENABLE

SION

SION PROTOCOL &

HANDLER

DATA

CHANNEL

1553

DATA

CHANNEL

LOGIC

HIGH-PRIORITY

STD PRIORITY LEVEL

STD PRIORITY PULSE

DMA ARBITRATION

DUAL-PORT MEMORY CONTROL

RT DESCRIPTOR SPACE

ENABLE

BUILT-IN-TEST

START COMMAND

RESET COMMAND

CONTROL

MONITOR ADDRESS

SELECT (0-15)

MONITOR ADDRESS

Figure 1. BCRTM Block Diagram

SELECT (16-31)

RT TIMER

RESET COMMAND

BCRTM-2

Table of Contents

1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.1 Features - Remote Terminal (RT) Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

1.2 Features - Bus Controller (BC) Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

1.3 Features - Monitor (M) Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

2.0 PIN IDENTIFICATION AND DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.0 INTERNAL REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4.0 SYSTEM OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

5.0 SYSTEM INTERFACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

5.1 DMA Transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

5.2 Hardware Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

5.3 CPU Interconnection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

5.4 RAM Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

5.6 Transmitter/Receiver Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

6.0 REMOTE TERMINAL ARCHITECTURE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

6.1 RT Functional Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

6.1.1 RT Subaddress Descriptor Definitions. . . . . . . . . . . . . . . . . . . . . . . . . .24

6.1.2 Message Status Word . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

6.1.3 Mode Code Descriptor Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

6.2 RT Error Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

6.3 RT Operational Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

7.0 BUS CONTROLLER ARCHITECTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.1 BC Functional Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

7.2 Polling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

7.3 BC Error Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

7.4 BC Operational Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

7.5 BC Operational Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

8.0 MONITOR ARCHITECTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8.1 Monitor Functional Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

8.2 Monitor Error Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

8.3 Monitor Operational Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

9.0 EXCEPTION HANDLING AND INTERRUPT LOGGING . . . . . . . . . . . . . . . . . . . . . . . . 36

10.0 MAXIMUM AND RECOMMENDED OPERATING CONDITIONS . . . . . . . . . . . . . . . . 40

11.0 DC ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

12.0 AC ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

13.0 PACKAGE OUTLINE DRAWINGS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

BCRTM-3

1.0 INTRODUCTION

The monolithic CMOS UT1553 BCRTM provides the

system designer with an intelligent solution to

MIL-STD-1553B multiplexed serial data bus design

problems. The UT1553B BCRTM is a single-chip device

that implements all three of defined MIL-STD-1553B

functions - Bus Controller, Remote Terminal, and Monitor.

Designed to reduce host CPU overhead, the BCRTM’s

powerful state machines automatically execute message

transfers, provide interrupts, and generate status

information. Multiple registers offer many programmable

functions as well as extensive information for host use. In

the BC mode, the BCRTM uses a linked-list message

scheme to provide the host with message chaining

capability. The BCRTM enhances memory use by

supporting variable-size, relocatable data blocks. In the RT

mode, the BCRTM implements time-tagging and message

history functions. It also supports multiple (up to 128)

message buffering and variable length messages to any

subaddress.In the Monitor (M) mode, the BCRTM’s

powerful linked list command block structure allows it to

process a series of monitored 1553 messages without the

intervention of the host. The BCRTM can store as much bus

traffic as can be contained in its 64K memory space. In

addition, the host has the capability of instructing the

BCRTM to monitor and store data for only selected remote

terminals.

The UT1553 BCRTM is an intelligent, versatile, and easy

to implement device -- a powerful asset to system designers.

1.1 Features - Remote Terminal (RT) Mode

Indexing

The BCRTM is programmable to index or buffer messages

on a subaddress-by-subaddress basis. The BCRTM, which

can index as many as 128 messages, can also assert an

interrupt when either the selected number of messages is

reached or every time a specified subaddress is accessed.

Variable Space Allocation

The BCRTM can use as little or as much memory (up to

64K) as needed.

Selectable Data Storage

Address programmability within the BCRTM provides

flexible data placement and convenient access.

Sequential Data Storage

The BCRTM stores/retrieves, by subaddress, all messages

in the order in which they are transacted.

Sequential Message Status Information

The BCRTM provides message validity, time-tag, and

word-count information, and stores it sequentially in a

separate, cross-referenced list.

Illegalizing Mode Codes and Subaddresses

The host can declare mode codes and subaddresses illegal

by setting the appropriate bit(s) in memory.

Programmable Interrupt Selection

The host CPU can select various events to cause an interrupt

with provision for high and standard priority interrupts.

Interrupt History List

The BCRTM provides an Interrupt History List that records,

in the order of occurrence, the events that caused the

interrupts. The list length is programmable.

1.2 Features - Bus Controller (BC) Mode

Multiple Message Processing

The BCRTM autonomously processes any number of

messages or lists of messages that may be stored in a 64K

memory space.

Automatic Intermessage Delay

When programmed by the host, the BCRTM can delay a

host-specified time before executing the next message in

sequence.

Automatic Polling

When polling, the BCRTM interrogates the remote

terminals and then compares their status word responses to

the contents of the Polling Compare Register. The BCRTM

can interrupt the host CPU if an erroneous remote terminal

status word response occurs.

Automatic Retry

The BCRTM can automatically retry a message on busy,

message error, and/or response time-out conditions. The

BCRTM can retry up to four times on the same or on the

alternate bus.

Programmable Interrupt Selection

The host CPU can select various events to cause an interrupt

with provision for high and standard priority interrupts.

Interrupt History List

The BCRTM provides an Interrupt History List that records,

in the order of occurrence, the events that caused the

interrupts. The list length is programmable.

Variable Space Allocation

The BCRTM uses as little or as much memory (up to 64K)

as needed.

Selectable Data Storage

Address programmability within the BCRTM provides

flexible data placement and convenient access.

BCRTM-4

1.3 Features - Monitor (M) Mode

Command History List

The BCRTM’s linked list command block structure permits

the BCRTM to process a series of monitored messages

without host intervention.

Monitor Selected Terminal Address

The host can select the remote terminals to be monitored by

programming the proper bits in the Terminal Address Select

registers (Registers16 and 17). The BCRTM can monitor

any or all remote terminals.

Variable Space Allocation

The BCRTM can use as little or as much memory (up to

64K) as needed

Selectable Data Storage

Address programmability within the BCRTM provides

flexible data placement and convenient access.

Sequential Data Storage

The BCRTM stores, by Terminal Address, all 1553

messages in the order in which they are transacted.

Programmable Interrupt Selection

The host can select a wide variety of events that may cause

an interrupting event.

Interrupt History List

The BCRTM stores, chronologically in memory, an

Interrupt History List of each event that causes an interrupt.

BCRTM-5

** Pin internally pulled up.

+Pin at high impedance when not asserted

++ Bidirectional pin.

*Formerly MEMWIN.

****

LCC, flatpack pin number not in parentheses.

() Pingrid array pin identification in parentheses.

TAZ

TAO

RAZ

RAO

TBZ

TBO

RBZ

RBO

RTA0

RTA1

RTA2

RTA3

RTA4

RTPTY

CLK

MCLK

MCLKD2

A10

A11

A12

A13

A14

A15

D10

D11

D12

D13

D14

D15

13 (K3)

14 (L2)

18 (L4)

(K6)

(L3)

(K5)

(L5)

(K4)

28 (K8) **

29 (L9) **

30 (L10) **

31 (K9) **

32 (L11) **

68 (A6)

69 (A4)

70 (B4)

25 (K7)

26 (J7)

27 (L8)

72 (A2)

75 (B2)

33 (K10) **

73 (B3)*

56 (A10)

57 (A9)

67 (B5)

58 (B8)

61 (B7)

60 (C7)

53 (A11)

52 (C10)

59 (A8)

54 (B10)

62 (A7)

55 (B9)

66 (A5)

(A3)

(K2)12

(A1)

10 (J2)

24 (L7)

34(J10) 35(K11) 36

(J11)

(H10)

(H11)

(G9)

(G10)

(G11)

(E9)

(E11)

(E10)

(F11)

(D11)

(D10)

(C11)

(B11)

(K1)

(J1)

(H2)

(H1)

(G3)

(G2)

(G1)

(F1)

(E1)

(E2)

(F2)

(D1)

(D2)

(C1)

(B1)

(C2)

(L6)

(F9)

(C6)

(E3)

(F3)

(J6)

(F10)

(B6)

(J5)

(C5) 71

(L1)

BIPHASE OUT

BIPHASE IN

TERMINAL

ADDRESS

STATUS

SIGNALS

DMA

SIGNALS

CONTROL

SIGNALS

ADDRESS

LINES

DATA

LINES

POWER

GROUND

CLOCK

SIGNALS

2.0 P

DENTIFICATION

ESCRIPTION

STDINTL

STDINTP

HPINT

TIMERON

COMSTR

SSYSF

BCRTF

CHA/B

TEST

DMAR

DMAG

DMAGO

DMACK

BURST

TSCTL

AEN

BCRTSEL

LOCK

MRST

EXTOVR

RRD

RWR

MEMCSI

MEMCSO

VDD

VSS

Figure 2. BCRT Functional Pin Description

BCRTM-6

A0 34

B11

TTB Bit 0 (LSB) of the Address bus

A10

A11

A12

C11

D10

D11

F11

E10

E11

G11

G10

H11

TTB

Bit 1 of the Address bus

Bit 2 of the Address bus

Bit 3 of the Address bus

Bit 4 of the Address bus

Bit 5 of the Address bus

Bit 6 of the Address bus

Bit 7 of the Address bus

Bit 8 of the Address bus

Bit 9 of the Address bus

Bit 10 of the Address bus

Bit 11 of the Address bus

H10

A13

A14

J11

K11

TTO

NAME PIN NUMBER

LCC PGA TYPE ACTIVE DESCRIPTION

A15 51

J10

TTB

TTO

Bit 12 of the Address bus

Bit 13 of the Address bus

Bit 14 of the Address bus

Bit 15 (MSB) of the Address bus

Legend for TYPE and ACTIVE fields:

TUI = TTL input (pull-up)

AL = Active low

AH = Active high

ZL = Active low - inactive state is high impedance

TI = TTL input

TO = TTL output

TTO = Three-state TTL output

TTB = Bidirectional

Notes:

1. Address and data buses are in the high-impedance state when idle.

2. Flatpack pin numbers are same as LCC.

BCRTM-7

TTB

9K1

Bit 0 (LSB) of the Data bus

Bit 1 of the Data bus

Bit 2 of the Data bus

Bit 3 of the Data bus

D10

D11

TTB

Bit 4 of the Data bus

Bit 5 of the Data bus

Bit 6 of the Data bus

Bit 7 of the Data bus

Bit 8 of the Data bus

Bit 9 of the Data bus

Bit 10 of the Data bus

Bit 11 of the Data bus

NAME TYPE ACTIVE DESCRIPTION

DATA BUS

D12

D13

D14

D15

TTB

Bit 12 of the Data bus

Bit 13 of the Data bus

Bit 14 of the Data bus

Bit 15 (MSB) of the Data bus

PIN NUMBER

LCC PGA

NAME TYPE ACTIVE DESCRIPTION

RTA0

TERMINAL ADDRESS INPUTS

28 K8 TUI Remote Terminal Address Bit 0 (LSB). The entire

RT address is strobed in at Master Reset. Verify it

by reading the Remote Terminal Address Register.

All the Remote Terminal Address bits are internally

pulled up.

RTA1 29 L9 TUI Remote Terminal Address Bit 1. This is bit 1 of

the Remote Terminal Address.

RTA2 30 L10 TUI Remote Terminal Address Bit 2. This is bit 2 of

the Remote Terminal Address.

RTA3 31 K9 TUI Remote Terminal Address Bit 3. This is bit 3 of

the Remote Terminal Address.

RTPTY 33 K10 TUI Remote Terminal (Address) Parity. This is an odd

parity input for the Remote Terminal Address.

RTA4 32 L11 TUI Remote Terminal Address Bit 4. This is bit 4

(MSB) of the Remote Terminal Address.

PIN NUMBER

LCC PGA

BCRTM-8

AEN 66 A5 TI AH

BCRTSEL 11 L1 TUI --

LOCK 12

TUI

10 J2 AL

NAME TYPE ACTIVE DESCRIPTION

CONTROL SIGNALS

B10

TUI

52 C10 TO AL

53 A11 TO AL

Read. The host uses this in conjunction with CS to read an

internal BCRTM register.

Write. The host uses this in conjunction with CS to write to an

internal BCRTM register.

BC/RT Select. This selects between either the Bus Con-

troller or Remote Terminal mode. The BC/RT Mode

Select bit in the Control Register overrides this input if

the LOCK pin is not high. This pin is internally

pulled high.

Lock. When set, this pin prevents internal changes

to both the RT address and BC/RT mode select functions.

This pin is internally pulled high.

External Override. Use this in multi-redundant applica-

tions. Upon receipt, the BCRTM aborts all current activ-

ity. EXTOVR should be connected to COMSTR output of

the adjacent BCRTM when used. This pin is internally

pulled high.

Memory Chip Select Out. This is the regenerated

MEMCSI input for external RAM during the pseudo-

dual-port RAM mode. The BCRTM also uses it to select

external memory during memory accesses.

EXTOVR

MRST

MEMCSO

MEMCSI

RRD

RWR

Memory Chip Select In. Used in the pseudo-dual-port

RAM mode only, MEMCSI is received from the host and

is propagated through to the MEMCSO.

RAM Read. In the pseudo-dual-port RAM mode, the host

uses this signal in conjunction with MEMCSO to read

from external RAM through the BCRTM. It is also the

signal the BCRTM uses to read from memory. It is

asserted following receipt of DMAG. When the BCRTM

performs multiple reads, this signal is pulsed.

RAM Write. In the pseudo-dual-port RAM mode, the

CPU and BCRTM use this to write to external RAM. This

signal is asserted following receipt of DMAG. For multi-

ple writes, this signal is pulsed.

PIN NUMBER

LCC PGA

Chip Select. This selects the BCRTM when accessing

the BCRTM’s internal register.

Address Enable. The host CPU uses AEN to indicate to the

BCRTM that the BCRTM’s address lines can be asserted;

this is a precautionary signal provided to avoid address bus

crash. If not used, it must be tied high.

Master Reset. This resets all internal state machines,

encoders, decoders, and registers. The minimum pulse

width for a successful Master Reset is 500ns.

BCRTM-9

TTO

NAME TYPE ACTIVE DESCRIPTION

TO AL

SSYSF

BCRTF

TEST

STATUS SIGNALS

(RT)Timer On. This is a 760-microsecond fail-safe trans-

mitter enable timer. Started at the beginning of a transmis-

sion. TIMERON goes inactive 760 microseconds later or

is reset automatically with the receipt of a new command.

Use it in conjunction with CHA/B output to provide a fail

safe timer for channel A and B transmitters.

Standard Interrupt Level. This is a level interrupt. It is

asserted when one or more events enabled in either the

Standard Interrupt Enable Register, RT Descriptor, or BC

Command Block occur. Resetting the Standard Interrupt

bit in the High-Priority Interrupt Status/Reset Register

clears the interrupt.

STDINTL

STDINTP Standard Interrupt Pulse. STDINTP pulses when an inter-

rupt is logged.

HPINT High Priority Interrupt. The High-Priority Interrupt level

is asserted upon occurrence of events enabled in the High

Priority Interrupt Enable Register. The corresponding

bit(s) in the High-Priority Interrupt Status/Reset Register

reset HPINT.

TIMERON

COMSTR

CHA/BChannel A/B. This indicates the active or last active

channel.

TEST. This pin is used as a factory test pin. (Formerly

MEMWIN.)

PIN NUMBER

LCC PGA

(RT) Command Strobe. The BCRTM asserts this

signal after receiving a valid command. The BCRTM deac-

tivates it after servicing the command.

Subsystem Fail. Upon receipt, this signal propagates

directly to the RT 1553 status word and the BCRTM

Status Register.

BCRT Fail. this indicates a Built-In-Test (BIT) failure.

In the RT mode, the Terminal Flag bit in 1553 status word

is also set.

NAME TYPE ACTIVE DESCRIPTION

BIPHASE INPUTS

RAO 16 K4 TI

RBO 20 L5 TI

RAZ

RBZ

PIN NUMBER

LCC PGA Receive Channel A One. This is the Manchester-en-coded

true signal input from Channel A of the bus receiver

Receive Channel A Zero. This is Manchester-encoded

complementary signal input from Channel A of the bus

receiver

Receive Channel B One. This is the Manchester-en-coded

true signal input from Channel B of the bus receiver.

Receive Channel B Zero. This is the Manchester-en-coded

complementary signal input from Channel B of the bus

receiver

BCRTM-10

NAME TYPE ACTIVE DESCRIPTION

TAO 14 L2 TO

TAZ 13 K3 TO

TBO 18 K6 TO

TBZ 17 L4 TO --

BIPHASE OUTPUTS

Transmit Channel A One. This is the Manchester-encoded

true output to be connected to the Channel A bus transmitter

input. This signal is idle low.

Transmit Channel A Zero. This is the Manchester-encoded

complementary output to be connected to the Channel A bus

transmitter input. This signal is idle low.

Transmit Channel B One. This is the Manchester-

encoded true output to be connected to the Channel B bus

transmitter input. This signal is idle low.

Transmit Channel B Zero. This is the Manchester-encoded

complementary output to be connected to the Channel B bus

transmitter input. This signal is idle low.

PIN NUMBER

LCC PGA

56 A10 ZL

TTO

NAME TYPE ACTIVE DESCRIPTION

DMA SIGNALS

55 B9 TO AL

BURST 74 A1 TO AH

DMA Request. The BCRTM issues this signal when access to

RAM is required. It goes inactive after receiving a DMAG

signal.

DMAR

DMAG

DMAGO

DMACK

TSCTL

DMA Grant Out. If DMAG is received but not needed, it

passes through to this output.

DMA Acknowledge. The BCRTM asserts this signal to confirm

receipt of DMAG, it stays low until memory access is complete.

PIN NUMBER

LCC PGA

DMA Grant. This input to the BCRTM allows the

BCRT to access RAM. It is recognized 45ns before the rising

edge of MCLKD2.

Three-State Control. This signal indicates when the

BCRTM is actually accessing memory. The host subsystem’s

address and data lines must be in the high-impedance state when

the signals active. This signal assists in placing the external data

and address buffers into the high-impedance state.

Burst (DMA Cycle). This indicates that the current

DMA cycle transfers at least two words; worst case is five words

plus a “dummy” word.

BCRTM-11

NAME TYPE ACTIVE DESCRIPTION

CLK

MCLK

MCLKD2

TO Memory Clock Divided by Two. This signal is the

Memory Clock input divided by two. It assists the

host subsystem in synchronizing DMA events.

Clock. The 12MHz input clock requires a 50%

± 10% duty cycle with an accuracy of ± 0.01%. The accuracy

is required in order to meet the Manchester encoding/

decoding requirements of MIL-STD-1553.

Memory Clock. This is the input clock frequency the BCRTM

uses for memory accesses. The memory cycle time is equal

to two MCLK cycles. Therefore, RAM access time is

dependent upon the chosen MCLK frequency (6MHz

minimum, 12MHz maximum). Please see the BCRTM DMA

timing diagrams in this data sheet.

CLOCK SIGNALS

PIN NUMBER

LCC PGA

NAME TYPE ACTIVE DESCRIPTION

G13

F10

PWR

GND

+5V

Ground

POWER AND

VDD

VSS

VDD

VSS

PIN NUMBER

LCC PGA

BCRTM-12

3.0 INTERNAL REGISTERS

The BCRTM’s internal registers (see table 1 on pages 18-

19) enable the CPU to control the actions of the BCRTM

while maintaining low DMA overhead by the BCRTM. All

functions are active high and ignored when low unless stated

otherwise. Functions and parameters are used in both RT

and BC modes except where indicated. Registers are

addressed by the binary equivalent of their decimal number.

For example, Register 1 is addressed as 0001B. Register

usage is defined as follows:

#0 Control Register

Bit

Number Description

BIT 15 Reserved.

BIT 14 Rt Address 31. When RT31=0, the BCRTM recognizes RT Address 31 as a Broadcast command. When

RT31=1,the BCRTM treats RT Address 31 as a normal terminal address.

BIT 13 Subaddress 31. When SA31=0, the BCRTM recognizes a command word with either subaddress 0 or 31 as being

a valid code. When SA31=1, the BCRTM only recognizes a command word with a subaddress of 0 as a valid

mode code.

BIT 12 Bus Controller Time out. When the BCRTM is a BC and BCTO=0, the BCRTM allows an RT up to 16us to

respond with a status word before it declares a bus time-out. If BCTO=1, the BCRTM allows an RT up to 32us to

respond with a status word before it declares a bus time-out. In the remote terminal mode of operation, this bit

controls to RT to RT response time-out. To support the requirements of MIL-STD-1553B, this bit is set to a

logical zero.

BIT 11 Enable External Override. For use in multi-redundant systems. This bit enables the EXTOVR pin.

BIT 10 BC/RT Select. This function selects between the Bus Controller and Remote Terminal/Monitor operation

modes. It overrides the external BCRTSEL input setting if the Change Lock-Out function is not used. A reset

operation must be performed when changing between BC and RT/M modes. For monitor operation this bit

must be "0". This bit is write-only.

BIT 9 (BC) Retry on Alternate Bus. This bit enables an automatic retry to operate on alternate buses. For example, if

on bus A, with two automatic retries programmed, the automatic retries occur on bus B.

BIT 8 (RT,M) Channel B Enable. When set, this bit enables Channel B operation.

(BC) No significance.

BIT 7 (RT,M) Channel A Enable. When set, this bit enables Channel A operation.

(BC) Channel Select A/B. When set, this bit selects Channel A.

BITs 6-5 (BC) Retry Count. These bits program the number (1-4) of retries to attempt. (00 = 1 retry, 11 = 4 retries)

BIT 4 (BC) Retry on Bus Controller Message Error. This bit enables automatic retries on an error the Bus Controller

detects (see the Bus Controller Architecture section, page 29).

BIT 3 (BC) Retry on Time-Out. This bit enables an automatic retry on a response time-out condition.

BIT 2 (BC) Retry on Message Error. This bit enables an automatic retry when the Message Error bit is set in the RT’s

status word response.

BIT 1 (BC) Retry on Busy. This bit enables automatic retry on a received Busy bit in an RT status word response.

BIT 0 Start Enable. In the BC mode, this bit starts/restarts Command Block execution. In the RT or M mode,

It enables the BCRTM to receive a valid command. RT operation does not start until a valid command is

received. When using this function:

•Restart the BCRTM after each Master Reset or programmed reset.

•This bit is not readable; verify operation by reading bit 0 of the BCRTM’s Status Register.

BCRTM-13

#1 Status Register (Read Only)

These bits indicate the BCRTM’s current status.

Bit

Number Description

BIT 15 TEST. This bit reflects the inverse of the TEST output. It changes state simultaneously with the TEST output.

BIT 14 (RT,M) Remote Terminal (or Monitor) Active. Indicates that the BCRTM, in the Remote Terminal (or Monitor)

mode, is presently servicing a command. This bit reflects the inverse of the COMSTR pin.

BIT 13 (RT) Dynamic Bus Control Acceptance. This bit reflects the state of the Dynamic Bus Control

Acceptance bit in the RT status word (see Register 10 on page 16).

BIT 12 (RT) Terminal Flag bit is set in RT status word. This bit reflects the result of writing to Register 10, bit 11

BIT 11 (RT) Service Request bit is set in RT status word.This bit reflects the result of writing to Register 10, bit 10.

BIT 10 (RT) Busy bit is set in RT status word.This bit reflects the result of writing to Register 10, bits 9 or 14.

BIT 9 BIT is in progress.

BIT 8 Reset is in progress. This bit indicates that either a write to Register 12 has just occurred or the BCRTM has

just received a Reset Remote Terminal (#01000) Mode Code. This bit remains set less than 1ms.

BIT 7 BC/(RT) Mode. Indicates the current mode of operation. A reset operation must be performed when changing

between BC and RT modes.

BIT 6 Channel A/B. Indicates either the channel presently in use or the last channel used.

BIT 5 Subsystem Fail Indicator. Indicates receiving a subsystem fail signal from the host subsystem on the

SSYSF input.

BITs 4-1 Reserved.

BIT 0 (BC) Command Block Execution is in progress. (RT) Remote Terminal is in operation. This bit reflects bit 0 of

#2 Current Command Block Register (BC,M)/Remote Terminal Descriptor Space Address Register (RT)

(BC) This register contains the address of the head pointer of the Command Block being executed. Accessing a new Command

Block updates it.

(RT) The host CPU initializes this register to indicate the starting location of the RT Descriptor Space. The host must allocate

320 sequential locations following this starting address. For proper operation, this location must start on an I x 512 decimal

address boundary, where I is an integer multiple.

(M) This register contains the address of the control/status word of the current Monitor Command Block. Accessing a new

Command Block updates it.

#3 Polling Compare Register

In the polling mode, the CPU sets the Polling Compare Register to indicate the RT response word on which the BCRTM should

interrupt. This register is 11 bits wide, corresponding to bit times 9 through 19 of the RT’s 1553 status word response. The

sync, Remote Terminal Address, and parity bits are not included (see the section on Polling, page 32).

BCRTM-14

#4 BIT (Built-In-Test) Word Register

The BCRTM uses the contents of this register when it responds to the Transmit BIT Word Mode Code (#10011). In addition,

the BCRTM writes to the two most significant bits of the BIT Word Register in response to either an Initiate Self-Test Mode

Code (RT mode) or a write to Register 11 (BIT Start Command) to indicate a BIT failure. If the BIT Word needs to be modified,

it can be read out, modified, then rewritten to this register. Note that if the processor writes a “1” to either bit 14 or 15 of this

Bit

Number Description

BIT 15 Channel B failure.

BIT 14 Channel A failure.

BIT 13-0 BIT Word. The least significant fourteen bits of the BIT Word are user programmable.

#5 Current Command Register (Read Only)

In the RT or Monitor mode, this register contains the command currently being processed. When not processing a command,

the BCRTM stores the last command or status word transmitted on the 1553B bus in this register. This register is updated only

when bit 0 of Register 0 is set. In the BC mode, this register contains the most current command sent out on the 1553B bus.

#6 Interrupt Log List Pointer Register

Initialized by the CPU, the Interrupt Log List Pointer Register indicates the start of the Interrupt Log List. After each list entry,

the BCRTM updates this register with the address of the next entry in the list. (See page 37.)

#7 High-Priority Interrupt Enable Register (Read/Write)

Setting the bits in this register causes a High-Priority Interrupt when the enabled event occurs. To service the High-Priority

Interrupt, the user reads Register 8 to determine the cause of the interrupt, then writes to Register 8 to clear the appropriate

bits. The BCRTM also provides a Standard Priority Interrupt Scheme that does not require host intervention. If High-Priority

Interrupt service is not possible in a given application, it is advisable to use the Standard Priority features.

Bit

Number Description

BITs 15-9 Reserved.

BIT 8 Data Overrun Enable. When set, this bit enables an interrupt when DMAG was not received by the BCRTM

within the allotted time needed for a successful data transfer to memory.

BIT 7 (BC) Illogical Command Error Enable. This bit enables a High-Priority Interrupt to be asserted upon the

occurrence of an Illogical Command. Illogical commands include incorrectly formatted RT-RT Command

Blocks.

BIT 6 (RT) Dynamic Bus Control Mode Code Interrupt Enable. When set, an interrupt is asserted when the

Dynamic Bus Control Mode Code is received.

BIT 5 Subsystem Fail Enable. When set, a High-Priority Interrupt is asserted after receiving a Subsystem Fail

(SSYSF) input pin.

BIT 4 End of BIT Enable. This bit indicates the end of the internal BIT routine.

BIT 3 BIT Word Fail Enable. This bit enables an interrupt indicating that the BCRTM detected a BIT failure.

BIT 2 (BC) End of Command Block List Enable (see Command Block Control Word, page 38.) This interrupt can be

superseded by other high-priority interrupts.

BIT 1 Message Error Enable. If enabled, a High-Priority Interrupt is asserted at the occurrence of a message error. If

a High-Priority Interrupt condition occurs, as the result of an enabled message error, the device will halt

operation until the user clears the interrupt by writing a “1” to Bit 1 of the High-Priority Interrupt Status/Reset

“locked up”), even if it receives a valid message. This High-Priority Interrupt scheme is necessary in order to

maintain the BCRTM’s state of operation so that the host CPU has this information available at the time of

interrupt service.

BIT 0 Standard Interrupt Enable. Setting this bit enables the STDINTL pin, but does not cause a high-priority

interrupt. If low, only the STDINTL pin is asserted when a Standard Interrupt occurs.

BCRTM-15

#8 High-Priority Interrupt Status/Reset Register

When a High-Priority Interrupt is asserted, this register indicates the event that caused it. To clear the interrupt signal and reset

the bit, write a “1” to the appropriate bit. See the corresponding bit definitions of Register 7, High-Priority Interrupt Enable

Bit

Number Description

BITs 15-9 Reserved.

BIT 8 Data Overrun.

BIT 7 Illogical Command.

BIT 6 Dynamic Bus Control Mode Received

BIT 5 Subsystem Fail.

BIT 4 End of BIT.

BIT 3 BIT Word Fail.

BIT 2 End of Command Block.

BIT 1 Message Error.

BIT 0 Standard Interrupt. The BCRTM sets this bit when any Standard Interrupt occurs, providing bit 0 of Register 7

is enabled.(Reset STDINTL output.)

#9 Standard Interrupt Enable Register

This register enables Standard Interrupt logging for any of the following enabled events (Standard Interrupt logging can also

occur for events enabled in the BC Command Block or RT Subaddress/Mode Code Descriptor):

Bit

Number Description

BITs 15-6 Reserved.

BIT 5 (RT) Illegal Broadcast Command. When set, this bit enables an interrupt indicating that an Illegal Broadcast

Command has been received.

BIT 4 (RT) Illegal Command. When set, this bit enables an interrupt indicating that an illegal command has been

received.

BIT 3 (BC) Polling Comparison Match. This enables an interrupt indicating that a polling event has occurred. The user

must also set bit 12 in the BC Command Block Control Word for this interrupt to occur.

BIT 2 (BC) Retry Fail. This bit enables an interrupt indicating that all the programmed number of retries have failed.

BIT 1 (BC, RT,M) Message Error Event. This bit enables a standard interrupt for message errors.

BIT 0 (BC,M) Command Block Interrupt and Continue. This bit enables an interrupt indicating that a Command

Block, with the Interrupt and Continue Function enabled, has been executed.

BCRTM-16

#10 Remote Terminal Address Register

This register sets the Remote Terminal Address via software. The Change Lock-Out Enable feature, when set, prevents the

Remote Terminal Address or the BCRTM Mode Selection from changing.

Bit

Number Description

BIT 15 (RT) Instrumentation. Setting this bit sets the RT status word Instrumentation bit.

BIT 14 (RT) Busy. Setting this bit sets the RT status word Busy bit. It does not inhibit data transfers to the subsystem.

BIT 13 (RT) Subsystem Fail. Setting this bit sets the RT status word Subsystem Flag bit. In the RT mode, the Subsystem

Fail is also logged into the Message Status Word.

BIT 12 (RT) Dynamic Bus Control Acceptance. Setting this bit sets the RT status word Dynamic Bus Control

Acceptance bit when the BCRTM receives the Dynamic Bus Control Mode Code from the currently active Bus

Controller. Host intervention is required for the BCRTM to take over as the active Bus Controller.

BIT 11 (RT) Terminal Flag. Setting this bit sets the RT status word Terminal Flag bit; the Terminal Flag bit in the RT

status word is also internally set if the BIT fails.

BIT 10 (RT) Service Request. Setting this bit sets the RT status word Service Request bit.

BIT 9 (RT) Busy Mode Enable. Setting this bit sets the RT status word Busy bit and inhibits all data transfers to the

subsystem.

BIT 8 BC/RT Mode Select. This bit’s state reflects the external pin BCRTSEL. It does not necessarily reflect the state

of the chip, since the BC/RT Mode Select is software-programmable via bit 10 of Register 0. This bit is

read-only.

BIT 7 Change Lock-Out. This bit’s state reflects the external pin LOCK. When set, this bit indicates that changes to the

RT address or the BC/RT Mode Select are not allowed using internal registers. This bit is read-only.

BIT 6 Remote Terminal Address Parity Error. This bit indicates a Remote Terminal Address Parity Error. It appears

after the Remote Terminal Address is latched if a parity error exists.

BIT 5 Remote Terminal Address Parity. This is an odd parity input bit used with the Remote Terminal Address. It

ensures accurate recognition of the Remote Terminal Address.

BITs 4-0 Remote Terminal Address (Bit 0 is the LSB). This reflects the RTA4-0 inputs at Master Reset. Modify the

Remote Terminal Address by writing to these bits.

#11 BIT Start Register (Write Only)

Any write (i.e., data = don’t care) to this register’s address location initiates the internal BIT routine, which lasts 100µs. Verify

using the BIT-in-Progress bit in the Status Register. A programmed reset (write to Register 12) must precede a write to this

The BCRTM’s self-test performs an internal wrap-around test between its Manchester encoder and its two Manchester decoders.

If the BCRTM detects a failure on either the primary or the secondary channel, it flags this failure by setting bit 14 of Register

4 (BIT Word Register) for Channel A and/or bit 15 for Channel B. When in the Remote Terminal mode, while the BCRTM is

performing its self-test, it ignores any commands on the 1553 bus until it has completed the self-test.

#12 Programmed Reset Register (Write Only)

Any write (i.e., data = don’t care) to this register’s address location initiates a reset sequence of the encoder/decoder and

protocol sections of the BCRTM which lasts less than 1 microsecond. This is identical to the reset used for the Reset Remote

Terminal Mode Code except that command processing halts. For a total reset (i.e., including registers), see the MRST signal

description.

BCRTM-17

#13 RT Timer Reset Register (Write Only)

Any write (i.e., data = don’t care) to this register’s address location resets the RT Time Tag timer to zero.

The BCRTM’s Remote Terminal Timer time-tags message transactions. The time tag is generated from a free-running eight-

bit timer of 64µs resolution. This timer can be reset to zero simply by writing to Register 13. When the timer is reset, it

immediately starts running.

#14 Activity Status/Operational Mode Register

BIT 15 Bus Monitor Select. This bit should be cleared for RT mode operation. The host sets this bit to enable the

BCRTM’s Monitor mode of operation. Bit 10 of Register 0 must also be "0" to enable the Monitor mode.

BIT 14 Monitor All Terminals. When this bit is set, the BCRTM monitors all remote terminal activity.If this bit is not set,

then bit 13 must be set. This bit should be cleared for RT Mode operation.

BIT 13 Monitor Declared Terminals. When this bit is set, the BCRTM monitors all remote terminal bus activity. If this

bit is not set, then bit 13 must be set.This bit should be cleared for RT mode operation.

BITs 12-0 Reserved

#15 Reserved Register

This register is reserved for BCRTM use only and the host should not access it.

#16 Monitor Selected Remote Terminal Address 15-0

BITs 15-0 Monitor Selected Remote Terminal Addresses 15-0. By setting the appropriate bit in this register, the host can

determine which or the Remote terminals, from RT 0 through RT 15, the BCRTM will monitor. For example,

by setting bit 5 in this register, the host instructs the BCRTM to only monitor the bus activity for remote terminal

5. These bits are not mutually exclusive, therefore, the host can monitor any number of different remote terminals

by selecting the proper combination of bits.

#17 Monitor Selected Remote Terminal Address 31-16

BITs 15-0 Monitor Selected Remote Terminal Addresses 31-16. By setting the appropriate bit in this register, the host can

determine which or the Remote terminals, from RT 16 through RT 31, the BCRTM will monitor. For example,

by setting bit 21 in this register, the host instructs the BCRTM to only monitor the bus activity for remote terminal

21. These bits are not mutually exclusive, therefore, the host can monitor any number of different remote

terminals by selecting the proper combination of bits on this register and Register 16.

BCRTM-18

76543210

89101112131415

76543210

89101112131415

76543210

89101112131415

76543210

89101112131415

RTYTO

UNUSEDUNUSEDUNUSEDUNUSED

BCTOUNUSEDUNUSEDUNUSED

A15 A14 A13 A12 A11 A10 A9 A8

A7 A6 A5 A4 A3 A2 A1 A0

(BC) CURRENT COMMAND BLOCK REGISTER

TEST RTACT DYNBUS RT FLAG SRQ BUSY BIT RESET

BC/RT BUSA/B SSFAIL CMBKPG

BC/RT STATUS REGISTER

EXTOVR BC/RT RTYALTB BUSBEN

BUSAEN

CHNSEL RTYCNT RTYBCME RTYME RTYBSY STEN

BC/RT CONTROL REGISTER

76543210

89101112131415

(RT) REMOTE TERMINAL DESCRIPTOR SPACE ADDRESS REGISTER

POLLING COMPARE REGISTER

TFDBCSS FLAGBUSYBRDCST SWBT14SWBT13SWBT12

SRQINSTRMSGERRXXXXX

D7 D6 D5 D4 D3 D2 D1 D0

CURRENT COMMAND REGISTER

D10 D9 D8

BIT WORD REGISTER

CHBFAIL CHAFAIL D13 D12 D11

76543210

89101112131415

D7 D6 D5 D4 D3 D2 D1 D0

D10 D9 D8D15 D14 D13 D12 D11

UNUSEDUNUSEDUNUSEDUNUSEDUNUSEDUNUSED

#6 INTERRUPT LOG LIST POINTER REGISTER

A0A1A2A3A4A5A6A7

A8A9A10A11A12A13A14A15

BCRTM HIGH-PRIORITYINTERRUPT ENABLE REGISTER

STDINTMSGERREOLBITFAILENDBITSSFAILDYNBUSILLCMD

DATOVRUNUSED

76543210

89101112131415

76543210

89101112131415

Table 1. BCRTM Registers

DATOVR

ILLCMD

BCRTM HIGH-PRIORITYINTERRUPT STATUS/RESET REGISTER#8 15 14 13 12 11 10 9 8

UNUSED UNUSED UNUSED UNUSED UNUSED UNUSED UNUSED

01234567

DYNBUS SSFAIL ENDBIT BITFAIL EOL MSGERR STDINT

BCRTM-19

#12

#13

PROGRAMMED RESET REGISTER

REMOTE TERMINAL TIMER RESET REGISTER

XXXXXXXX

76543210

89101112131415

XXXXXXXX

76543210

89101112131415

15 14 13 12 11 10 9 8

01234567

INSTR BUSY1BUSY2 SS FLAG DBC RT FLAG SRQ BC/RT

LOCK PARERR RTAPAR RTA4 RTA3 RTA2 RTA1 RTA0

ILLBCMD ILLCMD POLMTCH RTYFAIL MSGERR CMDBLK

BUILT-IN-TEST START REGISTER

REMOTE TERMINAL ADDRESS REGISTER

STANDARD INTERRUPT ENABLE REGISTER

#11

#10

#9 15 14 13 12 11 10 9 8

UNUSED UNUSED UNUSED UNUSED UNUSED UNUSED UNUSED UNUSED

01234567

UNUSED UNUSED

15 14 13 12 11 10 9 8

01234567

XXXXXXX

XXXXXXXX

#14 BUS MONITOR CONTROL REGISTER

XXXXXXXX

XXXXXMDTMATBMS

76543210

89101112131415

#16 MONITOR SELECTED REMOTE TERMINAL ADDRESES 0-15

TA0TA1TA7

TA8TA9TA10TA11TA12TA13TA14TA15

76543210

89101112131415

TA6 TA5 TA4 TA3 TA2

X = DON’T CARE

#17 MONITOR SELECTED REMOTE TERMINAL ADDRESES 16-31

TA16TA17T23

TA24TA25TA26TA27TA28TA29TA30TA31

76543210

89101112131415

T22 T21 T20 T19 TA18

Table 1. BCRTM Registers (continued from page 18)

BCRTM-20

4.0 SYSTEM OVERVIEW

The BCRTM can be configured for a variety of processor

and memory environments. The host processor and the

BCRTM communicate via a flexible, programmable

interrupt structure, internal registers, and a user-definable

shared memory area. The shared memory area (up to 64K)

is completely user-programmable and communicates

BCRTM control information -- message data, and status/

error information.

Built-in memory management functions designed

specifically for MIL-STD-1553 applications aid processor

off-loading. The host needs only to establish the parameters

within memory so the BCRTM can access this information

as required. For example, in the RT mode, the BCRTM can

store data associated with individual subaddresses

anywhere within its 64K address space. The BCRTM then

can automatically buffer up to 128 incoming messages of

the same subaddress, thus preventing the previous messages

from being overwritten by subsequent messages. This

buffering also extends the intervals required by the host

processor to service the data. Selecting an appropriate

MCLK frequency to meet system memory access time

requirements controls the memory access rate. The

completion of a user-defined task or the occurrence of a

user-selected event is indicated by using the extensive set

of interrupts provided.

In the BC mode, the BCRTM can process multiple

messages, assist in scheduling message lists, and provide

host-programmable functions such as auto retry. The

BCRTM is incorporated in systems with a variety of

interrupt latencies by using the Interrupt History List feature

(see Exception Handling and Interrupt Logging, page 37).

The Interrupt History List sequentially stores the events that

caused the interrupt in memory without losing information

if a host processor does not respond immediately to

an interrupt.

In the Monitor (M) mode, the BCRTM’s powerful linked

list command block structure allows it to process a series of

monitored 1553 messages without the intervention of the

host. The BCRTM can store as much bus traffic as can be

contained in its 64K memory space. In addition, the host has

the capability of instructing the BCRTM to monitor and

store data for only selected remote terminals. The host

system is responsible for initializing an area in memory that

tells the BCRTM where to store command word information

and data for each command that the BCRTM receives on

the 1553 bus. This area of memory consists of "Bus Monitor

Command Blocks." An M Command Block is very similar

to the BC Command Block in the BCRTM. The only real

differences are the direction of information flow, and that

there is no Head Pointer in the M Command Block.

5.0 SYSTEM INTERFACE

5.1 DMA Transfers

The BCRTM initiates DMA transfers whenever it executes

command blocks (BC mode) or services commands (RT

mode). DMAR initiates the transfer and is terminated by the

inactive edge of DMACK. The Address Enable (AEN)

input enables the BCRTM to output an address onto the

Address bus.

The BCRTM requests transfer cycles by asserting the

DMAR output, and initiates them when a DMAG input is

received. A DMACK output indicates that the BCRTM has

control of the Data and Address buses. The TSCTL output

is asserted when the BCRTM is actually asserting the

Address and Data buses.

To support using multiple bus masters in a system, the

BCRTM outputs the DMAGO signal that results from the

DMAG signal passing through the chip when a BCRTM bus

request was not generated (DMAR inactive). You can use

DMAGO in daisy-chained multimaster systems.

RAM

BCRTM

CPU MEMORY

CONTROL SIGNALS

RRD

RWR

MEMCSO

MEMCSI

Figure 3a. Pseudo-Dual-Port RAM

Control Signals

BCRTM-21

5.2 Hardware Interface

The BCRTM provides a simple subsystem interface and

facilitates DMA arbitration. The user can configure the

BCRTM to operate in a variety of memory-processor

environments including pseudo-dual-port RAM and

standard DMA configurations.

For complete circuit description, such as arbitration logic

and I/O, please refer to the appropriate application note.

5.3 CPU Interconnection

Pseudo-Dual-Port RAM Configuration

The BCRTM’s Address and Data buses connect directly to

RAM, with buffers isolating the BCRTM’s buses from those

of the host CPU (figures 3a and 3b). The CPU’s memory

control signals (RD, WR, and MEMCSI) pass through the

BCRTM and connect to memory as RRD, RWR, and

MEMCSO.

Standard DMA Configuration

The BCRTM’s and CPU’s data, address, and control signals

are connected to each other as shown in figures 3c and 3d.

The RWR, RRD, and MEMCSO are activated after DMAG

is asserted.

In either case, the BCRTM’s Address and Data buses remain

in a high-impedance state unless the CS and RD

signals are active, indicating a host register access; or

TSCTL is asserted, indicating a memory access by the

BCRTM. CPU attempts to access BCRTM registers are

ignored during BCRTM memory access. Inhibit DMA

transfers by using the Busy function in the Remote Terminal

Address Register while operating in the Remote

Terminal mode.

The designer can use TSCTL to indicate when the BCRTM

is accessing memory or when the CPU can access memory.

AEN is also available (use is optional), giving the CPU

control over the BCRTM’s Address bus. A DMA Burst

(BURST) signal indicates multiple DMA accesses.

Registers 0 through 13 are accessed with the decode of the

four LSBs of the Address bus (A0-A3) and asserting CS.

1553 BUS

BUS B

BUS A

XFMRXFMR

(DUAL REDUNDANT)

BCRTM CONTROL/ARBITRATIONCONTROL

CPU

HOST

BUFFERS

16 ADDRESS

16 DATA

RAM

DUAL

TRANSCEIVER

TRANSMITTER

TIMEOUT

Figure 3b. CPU/BCRTM Interface -- Pseudo-Dual-Port RAM Configuration

BCRTM-22

1553 BUS

BUS B

BUS A

XFMRXFMR

DUAL

TRANSCEIVER

MEMORY

ARBITRATION

CONTROL

ADDRESS

DATA

BCRTM CPU

RAM

BUFFER

Figure 3d. CPU/BCRTM Interface -- DMA Configuration

BCRTM

CPU

SHARED

MEMORY

AREA

•

ADDRESS BUS

DATA BUS

Figure 3c. DMA Signals

DMAR DMAG DMACK

RRD RWR MEMCSO

BCRTM-23

5.4 RAM Interface

The BCRTM’s RRD, RWR, and MEMCSO signals serve as

read and write controls during BCRTM memory accesses.

The host subsystem signals RD, WR, and MEMCSI

propagate through the BCRTM to become RRD, RWR, and

MEMCSO outputs to support a pseudo-dual-port. During

BCRTM-RAM data transfers, the host subsystem’s memory

signals are ignored until the BCRTM access is complete.

5.5 Legalization Bus

The BCRTM’s Manchester II encoder/decoder interfaces

directly with the1553 bus transceiver, using the TAO-TAZ

and RAZ-RAO signals for Channel A, and TBO-TBZ and

RBZ-RBO signals for Channel B.

The BCRTM also provides a TIMERON signal output and

an active channel output indicator (CHA/B) to assist in

meeting the MIL-STD-1553B fail-safe timer requirements..

6.0 REMOTE TERMINAL ARCHITECTURE

The Remote Terminal architecture is a descriptor-

based configuration of relevant parameters. It is composed

of an RT Descriptor Space (see figure 5) and internal, host-

programmable registers. The Descriptor Space contains

only descriptors. Descriptors contain programmable

subaddress parameters relating to handling message

transfers. Each descriptor consists of four words: (1) a

Control Word, (2) a Message Status List Pointer, (3) a Data

List Pointer, and (4) an unused fourth word (see figure 6.)

These words indicate how to perform the data transfers

associated with the designated subaddress.

BCRTM

CHANNEL A CHANNEL B

DUAL

TXINHA TXINHB

CHANNEL A CHANNEL B

TRANSCEIVER

TIMRONB

CHA/B

Figure 4. Dual-Channel Transceiver

#’S 15 & 31

#’S 1 & 17

#’S 0 & 16

- STARTING ADDRESS

INITIALIZED BY CPU

IN THE RT DESCRIPTOR

TRANSMIT

SUBADDRESS

#31

#31SUBADDRESS

MODE CODE

RECEIVE

UNUSED

TRANSMIT

UNUSED

SPACE REGISTER

Figure 5. Descriptor Space

FOR FUTURE EXPANSION

DATA LIST POINTER

MESSAGE STATUS LIST POINTER

INDEX

06815

UNUSED II

I I

9 7

ILLEGAL BROADCAST

SUBADDRESS

ILLEGAL

INTERRUPT WHEN

ADDRESSED

INTERRUPT WHEN

INDEX = 0

SUBADDRESS

Figure 6. Remote Terminal Subaddress Descriptor

BCRTM-24

A receive descriptor and a transmit descriptor are associated

with each subaddress. The descriptors reside in memory and

are listed sequentially by subaddress. By using the index

within the descriptor, the BCRTM can buffer incoming and

outgoing messages, which reduces host CPU overhead.

This message buffering also reduces the risk of incoming

messages being overwritten by subsequent incoming

messages.

Each descriptor contains a programmable interrupt structure

for subsystem notification of user-selected message

transfers and indicates when the message buffers are full.

Illegalizing subaddresses, in normal and broadcast modes,

is accomplished by using programmable bits within the

descriptor (see the RT Functional Operation section on

this page).

Message Status information -- including word count, an

internally generated time tag, and broadcast and message

validity information -- is provided for each message. The

Message Status Words are stored in a separate Message

Status Word list according to subaddress. The list’s starting

locations are programmable within the descriptor.

Message data, received or transmitted, is also stored in lists.

The message capacity of the lists and the lists’ locations are

user selectable within the descriptor.

6.1 RT Functional Operation

The RT off-loads the host computer of all routine data

transfers involved with message transfers over the 1553B

bus by providing a wide range of user-programmable

functions. These functions make the BCRTM’s operation

flexible for a variety of applications. The following

paragraphs give each function’s operational descriptions.

6.1.1 RT Subaddress Descriptor Definition

The host sets words within the descriptor (see figure 6). The

BCRTM then reads the descriptor words when servicing a

command corresponding to the specified descriptor. All bit-

selectable functions are active high and inhibited when low.

A. Control Word. The first word in the descriptor, the Control Word, selects or disables message transfers and selects an index.

Bit

Number Description

BITs

15-11 Reserved.

BIT 10 Illegal Broadcast Subaddress. Indicates to the BCRTM not to access this subaddress using broadcast

commands. The Message Error bit in the status word is set if the illegal broadcast subaddress is addressed.

Since transmit commands do not apply to broadcast, this bit applies only to receive commands.

BIT 9 Illegal Subaddress. Set by the host CPU, it indicates to the BCRTM that a command with this subaddress is

illegal. If a command uses an illegal subaddress the Message Error bit in the 1553 status word is set. The Illegal

Command Interrupt is also asserted if enabled.

BIT 8 Interrupt Upon Valid Command Received. Indicates that the BCRTM is to assert an interrupt every time a

command addresses this descriptor. The interrupt occurs just prior to post-command descriptor updating.

BIT 7 Interrupt When Index = 0. Indicates that the BCRTM initiates an interrupt when the index is decremented

to zero.

BITs 6-0 Index. These bits are for indexed message buffering. Indexing means transacting a pre-specified number of

messages before notifying the host CPU. After each message transaction, the BCRTM decrements the index by

one until index = 0. Note that the index is decremented for messages that contain message errors.

B. Message Status List Pointer. The host sets the Message Status List Pointer, the second word within the descriptor, and the

BCRTM uses it as a starting address for the Message Status List. It is incremented by one with each Message Status Word

write. If the Control Word Index is already equal to zero, the Message Status List Pointer is not incremented and the previous

Message Status Word is overwritten.

Note: A Message Status Word is written and the pointer is incremented when the BCRTM detects a message error.

C. Data List Pointer. The Data List Pointer is the third word within the descriptor. The BCRTM stores data in RAM beginning

at the address indicated by the Data List Pointer. The Data List Pointer is updated at the end of each successful message with

the next message’s starting address with the following exceptions:

•If the message is erroneous, the Data List Pointer is not updated. The next message overwrites any data

corresponding to the erroneous message.

•Upon receiving a message, if the index is already equal to zero, the Data List Pointer is not incremented and

data from the previous message is overwritten.

D. Reserved. The fourth descriptor word is reserved for future use.

BCRTM-25

6.1.2 Message Status Word

Each message the BCRTM transacts has a corresponding

Message Status Word, which is pointed to by the Message

Status List Pointer of the Descriptor. This word allows the

host CPU to evaluate the message’s validity, determine the

word count, and calculate the approximate time frame in

which the message was transacted (figures 7 and 8).

Message Status Word Definition

Bit

Number Description

BIT 15 Subsystem Failed. Indicates SSYSF was asserted before the Message Status Word transfer to memory. This

bit is also set when the user sets bit 13 of Register 10.

BIT 14 Broadcast Message. Indicates that the corresponding message was received in the broadcast mode.

BIT 13 Message Error. Indicates a message is invalid due to improper synchronization, bit count, word count, or

Manchester error.

BITs 12-8 Word Count. Indicates the number of words in the message and reflects the Word Count field in the command

word. Should the message contain a different number of words than the Word Count field, the Message Error

flag is triggered. If there are too many words, they are withheld from RAM. If the actual word count is less than

it should be, the Message Error bit in the 1553 status word is set.

BITs 7-0 Time Tag. The BCRTM writes the internally generated Time Tag to this location after message completion.

The resolution is 64µs. (See Register 13). If the timer reads 2, it indicates the message was completed 128 to

191µs after the timer started.

ASSERTED DURING THIS MESSAGE

MESSAGE ERROR

MESSAGE WAS BROADCASTED

SUBSYSTEM FAIL INPUT WAS

Figure 7. Message Status Word

WORD COUNT TIME TAG

15 14 13 12 8 7 0

MESSAGE

(FROM RT DESCRIPTOR)

Figure 8. Remote Terminal Data and Message Status List

LIST

MESSAGE STATUS WORD

DATA LIST

POINTER

DATA LIST

LIST POINTER

MESSAGE STATUS

BCRTM-26

6.1.3 Mode Code Descriptor Definition

Mode codes are handled similarly to subaddress

transactions. Both use the four-word descriptors residing in

the RT descriptor space to allow the host to program their

operational mode. Corresponding to each mode code is a

descriptor (see figure 9a). Of the 32 address combinations

for mode codes in MIL-STD-1553B, some are clearly

defined functions while others are reserved for future use.

Sixteen descriptors are used for mode code operations with

each descriptor handling two mode codes: one mode code

with an associated data word and one mode code without

an associated data word. All mode codes can be handled in

accordance with MIL-STD-1553B. The function of the first

word of the Mode Code Descriptor is similar to that of the

Subaddress Descriptor and is defined below. The remaining

three words serve the same purpose as in the

Subaddress Descriptor.

Control Word

Bit

Number Description

BIT 15 Interrupt on Reception of Mode Code (without Data Word).

BIT 14 Illegalize Broadcast Mode Code (without Data Word).

BIT 13 Illegalize Mode Code (without Data Word).

BIT 12 Reserved.

BIT 11 Illegalize Broadcast Mode Code (with Data Word).

BIT 10 Illegalize Transmit Mode Code (with Data Word).

BIT 9 Illegalize Receive Mode Code (with Data Word).

BIT 8 Interrupt on Reception of Mode Code (with Data Word).

BIT 7 Interrupt if Index = 0.

BITs 6-0 Index. Functionally equivalent to the index described in the Subaddress Descriptor. It applies to mode codes with

data words only.

Figure 9a. (RT) Mode Code Descriptor Space

RTDSSA + 320

MODE CODE

MODE CODE (RTDSSA) + 256

STARTING ADDRESS

DESCRIPTOR SPACE

REMOTE TERMINAL

#’S 15 & 31

#’S 2 & 18

#’S 1 & 17

#’S 0 & 16

MODE CODE

Note:

Mode code descriptor blocks are also provided for reserved mode

codes but have no associated predefined BCRTM operation.

15 14 13 12 11 10 9 8 7 6 0

MESSAGE STATUS LIST POINTER

DATA LIST POINTER

RESERVED

INDEX

ILLEGALIZE BROADCAST MODECODE

(WITHOUT DATA WORD)

INTERRUPT ON RECEPTION OF MODE CODE

(WITHOUT DATA WORD)

ILLEGALIZE MODE CODE

(WITHOUT DATA WORD)

RESERVED

ILLEGALIZE BROADCAST MODECODE

(WITH DATA WORD)

ILLEGALIZE RECEIVE MODE CODE

(WITH DATA WORD)

INTERRUPT ON RECEPTION OF MODE CODE

(WITH DATA WORD)

INTERRUPT IF INDEX = 0

ILLEGALIZE TRANSMIT MODE CODE

(WITH DATA WORD)

Figure 9b. (RT) Mode Code Descriptor

BCRTM-27

The descriptors, numbered sequentially from 0 to 15,

correspond to mode codes 0 to 15 without data words and

mode codes 16 to 31 with data words. For example, mode

codes 0 and 16 correspond to descriptor 0 and mode codes

1 and 17 correspond to descriptor 1. The Mode Code

Descriptor Space is appended to the Subaddress Descriptor

Space starting at 0100H (256D) of the 320-word RT

Descriptor Space (see figure 5).

The BCRTM can autonomously support all mode codes

without data words by executing the specific function and

transmitting the 1553 status word. The subsystem provides

the data word for mode codes with data words (see the Data

List Pointer section). For all mode codes, an interrupt can

be asserted by setting the appropriate bit in the control word

upon successful completion of the mode command by

setting the appropriate bit in the control word (see figure 9b).

Dynamic Bus Control #00000

This mode code is accepted automatically if the Dynamic

Bus Control Enable bit in the Remote Terminal Address

Acceptance bit in the 1553 status word and BCRTM Status

Priority Interrupt is also asserted if enabled. If the Dynamic

Bus Control Enable bit is not set, the BCRTM does not

accept Dynamic Bus Control.

Synchronize (Without Data Word) #00001

If enabled in the Mode Code #00001 Descriptor Control

Word, the BCRTM asserts an interrupt when this mode code

is received.

Transmit Status Word #00010

The BCRTM automatically transmits the 1553 status word

corresponding to the last message transacted.

Initiate Self-Test #00011

The BCRTM automatically starts its BIT routine. An

interrupt, if enabled, is asserted when the test is completed.

The BIT Word Register and external pin BCRTF are updated

when the test is completed. A failure in BIT will also set the

TF status word bit.

Transmitter Shutdown #00100

The BCRTM disables the channel opposite the channel on

which the command was received.

Override Transmitter Shutdown #00101

The BCRTM enables the channel previously disabled.

Inhibit Terminal Flag Bit #00110

The BCRTM inhibits the Terminal Flag from being set in

the status word.

Override Inhibit Terminal Flag Bit #00111

The BCRTM disables the Terminal Flag inhibit.

Reset Remote Terminal #01000

The BCRTM automatically resets the encoder, decoders,

and protocol logic.

Transmit Vector Word #10000

The BCRTM transmits the vector word from the location

addressed by the Data List Pointer in the Mode Code

Descriptor Block.

Synchronize (with Data Word) #10001

On receiving this mode code, the BCRTM simply stores the

associated data word.

Transmit Last Command #10010

The BCRTM transmits the last command executed and the

corresponding 1553 status word.

Transmit BIT Word #10011

The BCRTM transmits BIT information from the BIT

Selected Transmitter Shutdown #10100

On receiving this mode code, the BCRTM simply stores the

associated data word.

Override Selected Transmitter Shutdown #10101

On receiving this mode code, the BCRTM simply stores the

associated data word.

BCRTM-28

6.2 RT Error Detection

In accordance with MIL-STD-1553B, the remote terminal

handles superseding commands on the same or opposite bus.

When receiving, the Remote Terminal performs a response

time-out function of 56µs for RT-RT transfers. If the

response time-out condition occurs, a Message Error bit can

be set in the 1553 status word and in the Message Status

Word. Error checking occurs on both of the Manchester

logic and the word formats. Detectable errors include word

count errors, long words, short words, Manchester errors

(including zero crossing deviation), parity errors, and data

discontiguity.

6.3 RT Operational Sequence

The following is a general description of the typical

behavior of the BCRTM as it processes a message in the RT

mode. It is assumed that the user has already written a “1”

to Register 0, bit 0, enabling RT operation.

Valid Command Received.

COMSTR goes active

•DMA Descriptor Read. After receiving a valid

command, the BCRTM initiates a burst DMA:

DMA arbitration (BURST)

Control Word read

Message Status List Pointer read

Data List Pointer read

Data Transmitted/Received.

•Data Word DMA.

If the BCRTM needs to transmit data from memory,

it initiates a DMA cycle for each Data Word shortly

before the Data Word is needed on the 1553B bus:

DMA arbitration

Data Word read (starting at Data List Pointer

address, incremented for each successive

word)

If the BCRTM receives data, it writes each Data

Word to memory after the Data Word is received:

DMA arbitration

Data Word write (starting at Data List Pointer

address, incremented for each successive

word)

Status Word Transmission.

The BCRTM automatically transmits the Status

Word as defined in MIL-STD-1553B.The Message

Error and Broadcast Command Received bits are

generated internally.Writing to Register 10 enables

the other predefined bits. For illegalized commands,

the BCRTM also sets the Message Error Bit in the

1553 Status Word.

Exception Handling.

If an interrupting condition occurs during the

message, the following occurs:

For High-Priority Interrupts:

HPINT is asserted (if enabled in Register 7).

For message errors, the BCRTM is put in a

hold state until the interrupt is acknowledged

(by writing a “1” to the appropriate bit in

For Standard Interrupts:

DMA arbitration (BURST)

Interrupt Status Word write

RT Descriptor Block Pointer write

Tail Pointer read (into Register 6)

STDINTP pulses low

STDINTL asserted (if enabled)

Processing continues

•Descriptor Write.

After the BCRTM processes the message, a final

DMA burst occurs to update the descriptor block, if

necessary:

DMA arbitration (BURST)

Message Status Word write

Data List Pointer write

(incremented by word count)

Message Status List Pointer write

(incremented by 1)

Control Word write (index decremented)

Note the following exceptions:

Mode codes without data require no

descriptor update.

Predefined mode codes (18 and 19) which do

not require access to memory for the data

word, do not involve updating the Data List

Pointer.

Messages with errors prevent updates to the

Data List Pointer.

If the message index was zero, neither the

Message Status List Pointer nor the Data List

Pointer is updated.

BCRTM-29

7.0 BUS CONTROLLER ARCHITECTURE

The BCRTM’s bus controller architecture is based on a

Command Block structure and internal, host-

programmable registers. Each message transacted over the

MIL-STD-1553B bus has an associated Command Block,

which the CPU sets up (see figures 11 and 12). The

Command Block contains all the relevant message and RT

status information as well as programmable function bits

that allow the user to select functions and interrupts. This

memory interface system is flexible due to a doubly-linked

list data structure

Figure 10. Command Block

In a doubly-linked Command Block structure, pointers

delimit each Command Block to the previous and

successive blocks (see figure 12). The linking feature eases

multiple message processing tasks and supports message

scheduling because of its ability to loop through a series of

transfers at a predetermined cycle time. A data pointer in

the command allows efficient space allocation because data

blocks only have to be configured to the exact word count

used in the message. Data pointers also provide flexibility

in data-bank switching.

A control word with bit-programmable functions and a

Message Error bit are in each Command Block. This allows

selecting individual functions for each message and

provides message validity information. The BCRTM’s

address pointers.

A programmable auto retry function is selectable from the

control word and Control Register.

The auto retry can be activated when any of the following

occurs:

•Busy Bit set in the status word

•Message Error (indicated by the RT status response)

•Response Time-Out

•Message Error detected by the Bus Controller

One to four retries are programmable on the same or

opposite bus.

The Bus Controller also has a programmable intermessage

delay timer that facilitates message transfer scheduling (see

figures 13 and 14). This timer, programmed in the control

word, automatically delays between the start of two

successive commands.

A polling function is also provided. The Bus Controller,

when programmed, compares incoming status words to a

host-specified status word and generates an interrupt if the

comparison indicates any matching bits. An Interrupt and

Continue function facilitates the host subsystem’s

synchronization by generating an interrupt when the

specified Command Block’s message is executed.

HEAD POINTER

CONTROL WORD

COMMAND WORD 1

COMMAND WORD 2 (RT-RT ONLY)

DATA LIST POINTER

STATUS WORD 1

STATUS WORD 2 (RT-RT ONLY)

TAIL POINTER

X IS BETWEEN 1 & 32

LAST DATA WORD

DATA WORD #2

DATA WORD #1

DATA LIST POINTER

COMMAND BLOCK

Figure 11. Data Placement

COMMAND BLOCK #1

Figure 12. Command Block Chaining

BCRTM-30

7.1 BC Functional Operation

The Bus Controller off-loads the host computer of many

functions needed to coordinate 1553B bus data transfers.

Special architectural features provide message- by-message

flexibility. In addition, a programmable interrupt scheme,

programmable intermessage timing delays, and internal

registers enhance the BCRTM’s operation.

The host determines the first Command Block by setting the

initial starting address in the current Command Block

Command Block Register with the next Command Block

Address. The BCRTM then executes the sequential

Command Blocks and counts out message delays (where

programmed) until it encounters the last Command Block

listed (indicated by the End of List bit in the control word).

Interrupts are asserted when enabled events occur (see

section 9.0, Exception Handling and Interrupt Logging).

The functions and their programming instructions are

described below. The registers also contain many

programmable functions and function parameters.

BC Command Block Definition

Each Command Block contains (see figure 10):

A. Head Pointer. Host-written, this location can contain the address of the previous Command Block’s Head Pointer.

The BCRTM does not access this location.

B. Control Word. Host-written, the Control Word contains bit-selectable options and a Message Error bit the

BCRTM provides (see figure 13). The bit definitions follow.

Bit

Number Description

BIT 15 Message Error. The BCRTM sets this bit when it detects an invalid RT response as defined in

MIL-STD 1553B.

BIT 14 Skip. When set, this bit instructs the BCRTM to skip this Command Block and execute the next.

BIT 13 Interrupt and Continue. If set, a Standard Interrupt is asserted when this block is addressed; operation,

however, continues. Note that this interrupt must also be enabled by setting bit 0 of Register 9.

BIT 12 Polling Enable. Enables the BCRTM’s polling operation.

BIT 11 Auto Retry Enable. When set, the Auto Retry function, governed by the global parameters in the Control

BIT 10 End of List. Set by the CPU, this bit indicates that the BCRTM, upon completion of the current message,

will halt and assert a High-Priority Interrupt. The interrupt must also be

enabled in the High-Priority Interrupt Enable Register.

BIT 9 RT-RT. Set by the CPU, this indicates that this Command Block transacts an RT-RT transfer.

‘TIME DELAY’

TRANSFER

RT-RT

MONITOR

TRANSFER

RT-RT

LIST

END

ENABLE

RETRY

AUTO

ENABLE

POLLING

CONTINUE

AND

INTERRUPT

ERROR

MESSAGE SKIP

15 14 13 12 11 10 9 8 7 0

Figure 13. Command Word

Figure 14. BC Timing Delays

MESSAGE #1 MESSAGE #2 MESSAGE #3

TDELAY1 TDELAY2

BCRTM-31

BIT 8 Monitor RT-RT Transfer. Set by the CPU, this function indicates that the BCRTM should receive and store

the message beginning at the location indicated by the data pointer.

BITs 7-0 Time Delay. The CPU sets this field, which causes the BCRTM to delay the specified time between sequential

message starts (see figures 13 and 14). Regardless of the value in the Time Delay field (including zero), the

BCRTM will at least meet the minimum 4µs intermessage gap time as specified in MIL-STD-1553B. The

timer is enabled by having a non-zero value in this bit field. When using this function, please note:

•Timer resolution is 16µs. As an example, if a given message requires 116µs to complete (including the minimum

4ms intermessage gap time) the value in the Time Delay field must be at least 00001000

(8 x 16µs = 128µs) to provide an intermessage gap greater than the 4ms minimum requirement.

•If the timer is enabled and the Skip bit is set, the timer provides the programmed delay before proceeding.

•If the message duration exceeds the timer delay, the message is completed just as if the time were

not enabled.

•If SKIP = 1 and EOL = 1 the HPINT is generated if enabled

•If SKIP = 1 and Interrupt and Continue = 1, the STDINT is generated

C. Command Word One. Initialized by the CPU, this location contains the first command word corresponding to the

Command Block’s message transfer.

D. Command Word Two. Initialized by the CPU, this location is for the second (transmit) command word in RT-RT

transfers. In messages involving only one RT, the location is unused.

E. Data Pointer. Initialized by the CPU, this location contains the starting location in RAM for the command block’s

message (see figure 15).

F. Status Word One. Stored by the BCRTM, this location contains the entire Remote Terminal status response.

G. Status Word Two. Stored by the BCRTM, this location contains the receiving Remote Terminal status word. For

transfers involving one Remote Terminal, the location is unused.

H. Tail Pointer. Initialized by the host CPU, the Tail Pointer contains the next Command Block’s starting address.

7.2 Polling

During a typical polling scenario (see figure 16) the Bus

Controller interrogates remote terminals by requesting them

to transmit their status words. This feature can also alert the

host if a bit is set in any RT status word response during

normal message transactions. The BCRTM enables the host

to initialize a chain of Command Blocks with the command

word’s Polling Enable bit. A programmable Polling

Compare Register (PCR) is provided. In the polling mode,

the Remote Terminal response is compared to the Polling

Compare Register contents. Program the PCR by setting the

PCR bits corresponding to the RT’s 1553 status word bits

to be compared. If they match (i.e., two 1’s in the same bit

position) then, if enabled in both the BC Command Block

Control Word and in the Standard Interrupt Enable Register

(Register 9), a polling comparison interrupt is generated.

Example 1. No bit match is present

PCR 00000000001

RT’s 1553 Status Word response 00000100010

Result No Polling Comparison Interrupt

Example 2. Bit match is present

PCR 00100100000

RT’s 1553 Status Word response 00000100000

Result Polling Comparison Interrupt

7.3 BC Error Detection

The Bus Controller checks for errors (see the Exception

Handling and Interrupt Logging and the RT Error Detection

sectons, pages 37 and 28) on each message transaction. In

addition, the BC compares the RT command word addresses

to the incoming status word addresses. The BC monitors for

response time-out and checks data and control words for

proper format according to MIL-STD-1553. Illogical

commands include incorrectly formatted RT-RT

Command Blocks.

Figure 15. Contiguous Data Storage

COMMAND BLOCK #1

DATA POINTER

COMMAND BLOCK #2

DATA POINTER

MESSAGE #1

MESSAGE #2

RAM

DATA WORD #1

DATA WORD #2

DATA WORD #3

DATA WORD #1

DATA WORD #2

DATA WORD #3

DATA WORD #4

BCRTM-32

7.4 Bus Controller Operational Sequence

The following is a general description of the typical

behavior of the BCRTM as it processes a message in the

BC mode.

The user starts BC operation by writing a “1” to Register

0, Bit 0.

•Command Block DMA - the following occurs

immediately after Bus Controller startup:

DMA arbitration (BURST)

Control Word read

Command Word 1 read (from third location

of Command Block)

Data List Pointer read

A. For BC-to-RT Command Blocks:

The BCRTM transmits the Command Word.

•Data Word DMA

DMA arbitration

Data Word read (starting at Data List Pointer

address, incremented for each successive

word)

The BCRTM transmits the Data Word. Data Word DMAs

and transmissions continue until all Data Words are

transmitted.

•Status Word DMA

The BCRTM receives the RT Status Word.

DMA arbitration

Status Word write (to sixth location of

Command Block)

B. For RT-to-BC Command Blocks:

The BCRTM transmits the Command Word.

•Status Word DMA

The BCRTM receives the RT Status Word.

DMA arbitration

Status Word write (to sixth location of

Command Block)

The BCRTM receives the first Data Word.

•Data Word DMA

DMA arbitration

Data Word write (starting at Data List

Pointer address, incremented for each

successive word)

Data Word receptions and DMAs continue until all Data

Words are received.

C. For RT(A)-to-RT(B) Command Blocks:

The BCRTM transmits Command Word 1 to RT(B).

•Command Word 2 DMA

DMA arbitration

Command Word 2 read (from fourth location

of Command Block)

The BCRTM transmits Command Word 2 to RT(A).

The BCRTM receives the RT Status Word from RT(A).

•Status Word DMA for RT(A) Status Word

DMA arbitration

Status Word write (to sixth location of

Command Block)

The BCRTM receives the first Data Word

•Data Word DMA (only if the BCRTM is enabled to

monitor the RT-to-RT message).

DMA arbitration

Data Word write (starting at Data List Pointer

address, incremented for each successive

word)

Data Word receptions and DMAs continue until all Data

Words are received.

The BCRTM receives the RT Status Word from RT(B).

•Status Word DMA for RT(B) Status Word

DMA arbitration

Status Word write (to seventh location of

Command Block)

RESPONSE

RTRT

POLLING RESPONSE REGISTER

(RT STATUS WORD)

POLLING COMPARE WORD

(SET BY CPU)

Figure 16. Polling Operation

BCRTM-33

Exception Handling.

If an interrupting condition occurs during the message,

the following occurs:

For High-Priority Interrupts:

HPINT is asserted (if enabled in Register 7). For message

errors, the BCRTM is put in a hold state until the

interrupt is acknowledged (by writing a “1” to the

appropriate bit in Register 8).

For Standard Interrupts:

DMA arbitration (BURST)

Interrupt Status Word write

Command Block Pointer write

Tail Pointer read (into Register 6)

STDINTP pulses low

STDINTL asserted (if enabled)

Processing continues

If Retries are enabled and a Retry condition occurs, the

following DMA occurs:

DMA arbitration (BURST)

Control Word read

Command Word 1 read (from third location

of Command Block)

Data List Pointer read

The BCRTM proceeds from the current Command Block to

the next successive Command Block.

•If no Message Error has occurred during the current

Command Block, the following occurs:

DMA arbitration (BURST)

Command Block Tail Pointer read (to

determine location of next Command Block.

Note that this occurs only if no Retry).

DMA hold cycle

Control Word read (next Command Block)

Command Word 1 read (next Command

Block)

Data List Pointer read

•If the BCRTM detects a Message Error while

processing the current Command Block, the following

occurs:

DMA arbitration (BURST)

Control Word write

Command Block Tail Pointer read (to

determine location of next Command Block.

Note that this occurs only if no Retry.)

DMA hold cycle

Control Word read (next Command Block)

Command Word 1 read (next Command

Block)

Data List Pointer read

The BCRTM proceeds again from point A, B, or C as

shown above.

7.5 BC Operational Example (figure 22)

The BCRTM is programmed initially to accomplish the

following:

The first Command Block is for a four-word RT-RT transfer

with the BCRTM monitoring the transfer and storing

the data.

•Auto-retry is enabled on the opposite bus using only

one retry attempt, if the incoming Status Word is

received with the Message Error bit set.

•Wait for a time delay of 400 microseconds before

proceeding to the next Command Block.

•The Data List Pointer contains the address 0400H.

The second Command Block is for a BC-RT transfer of

two words.

•The End of List bit is set in its Control Word.

•The Data List Pointer contains the address 0404H.

•The Polling Enable bit is set and the Polling Compare

(Bit 2).

Then:

A. The CPU initializes all the appropriate registers and

Command Blocks, and issues a Start Enable by writing

a “1” to Register 0, Bit 0.

B. The BCRTM, through executing a DMA cycle, reads

the Control Word, Command Words, and the Data List

Pointer. The delay timer starts and message execution

begins by transmitting the receive and transmit

commands stored in the Command Blocks. The

BCRTM then waits to receive the Status Word back

from the transmitting RT.

C. The BCRTM receives the RT Status Word with all status

bits low from the transmitting RT and stores the Status

Word in Command Block 1. The incoming data words

from the transmitting RT follow. The BCRTM stores

them in memory locations 0400H - 0403H.

If the Status Word indicates that the message cannot be

transmitted (Message Error), the response time-out

clock counts to zero and the allotted message time runs

out. An auto-retry can be initiated if programmed to do

so. Nevertheless, the ME bit in the Control Word is set.

BCRTM-34

D. The BCRTM receives the Status Word response from

the receiving RT. The ME bit in the Status Word is set,

indicating the message is invalid. The BCRTM initiates

the auto retry function, (as programmed) on the

alternate bus, re-transmits the Command Words,

receives the correct Status Word, and stores the data

again in locations 0400H - 0403H. This time the Status

Word response

from the receiving RT indicates the message transfer

is successful.

E. The timer delay between the two successive

transactions counts down another 135µs before

proceeding. This is determined as follows:

The message transaction time is approximately130µs

(the only approximation is due to the range in status

response and intermessage gap times specified by MIL-

STD-1553B). Approximating that with the retry, the

total duration for the two attempts is 265µs.

F. The BCRTM reads the Tail Pointer of Command Block

1 and places it in the Current Command Register. It also

reads the Control Word, Command Word, and Data

List Pointer, and the first data word in the second

Command Block.

G. Since this is a BC-RT transfer, the BCRTM transmits

the receive command followed by two data words from

locations 0404H - 0405H in memory. The BCRTM

reads the second data word from memory while

transmitting the first.

H. The BCRTM receives the status response from the RT.

In this case, the Status Word indicates, by the ME bit

being low, that the message is valid. The Status Word

also has the Subsystem Fail bit set.

I. The Status Word is stored in the Command Block. The

BCRTM, having encountered the end of the list, halts

message transactions and waits for another start signal.

J. The BCRTM asserts a High-Priority Interrupt

indicating the end of the command list. Due to the

polling comparison match, the BCRTM also asserts a

Standard Priority Interrupt and logs the event in the

Interrupt

Log List.

8.0 BUS MONITOR ARCHITECTURE

The BCRTM’s bus monitor architecture is based on a

Command Block structure and internal, host-programmable

registers. Each message transactedover the MIL-STD-

1553B bus (for a monitored RT address) has an associated

Command Block, which the CPU sets up (see figures 17 and

18). The Command Block contains all the relevant message

and RT status information as well as programmable function

bits that allow the user to select functions and interrupts.

Figure 17 BCRTM Bus Monitor Command Block

In a linked list Command Block structure, pointers delimit

each Command Block to the successive block (see figure 19)

A data pointer9 in theCommand Block allows efficient

space allocation because data blocks do not have to be

placed contiguosly in memory

A Monitor control/status word with an eight-bit Time Tag,

an Interrupt When Addressed bit, a Message Error bit, and

a Command Block Activated bit are in each Monitor

Command Block. The user can access these control/status

words to determine which Monitor Command Block, the

host can determine when particular remote terminal

has occured.

MONITOR CINROL/STATUS

1553 COMMAND WORD 1

1553 COMMAND WORD

DATA LIST POINTER

1553 STATUS WORD 1

1553 STATUS WORD 2

TAIL POINTER

COMMAND BLOCK #1

DATA LIST POINTER

Figure 18. Data Placement

DATA WORD #1

DATA WORD #2

X IS BETWEEN 1 & 32

LAST DATA WORD

BCRTM-35

8.1 Monitor Functional Operation

The Bus Monitor function is a register-selectable mode of

operation. The host users registers 14, 16, and 17 in

conjunction with Register 0 to program the BCRTM to

monitor any combination of remote terminals or all of the

remote terminals.

the BCRTM’s memory mangement scheme gives the host a

great deal of flexibility for processing 1553 bus data and is

compatible with may bus monitoring applications. the host

CPU is responsible for processing initializing the Monitor

Control Blocks. The Monitor structure is analogous to the

Bus Controller Command Block scheme. the only real

difference is the direction of information flow.

The number of Monitor Control Blocks that the host

initializes depends on the data latency requirements for

post-processing of 1553 commands. the linked list of

Command Blocks could be connected in a loop fashion, with

the BCRTM accessing the loop at one point and the host

CPU processing the message behind that point. The bit

positions of the BM control/status word are defined as

shown in figure 20.

8.2 Monitor Error Detection

in the Monitor mode, the BCRTM chaecks all monitored

messages for errors. Detectable errors include word count

errors, long words, short words, Manchester errors

(including zero crossing deviation), parity errors, and

data contiguity.

Due to the nature of the 1553 protocol, it ca be very difficult

for any monitoring device to interpret some types of errors

on the 1553 bus. For example, suppose an RT (whose RT

Address the BCRTM is monitoring) incorrectly responds to

a Broadcast command. The BCRTM, which is not receiving

or transmitting the message, cannot distinguish between the

erroneous status word and a new command sent from the

Bus Controller, since the status syncis identified to the

command sync. In this case, the BCRTM will put the extra

status word in a new Monitor Command Block, and then

report a Message Error due to the to the incorrect

protocol on the erroneously interpreted status word the

RT transmitted.

8.3 Monitor Operational Sequence

The following is a general description of the operation of

the BCRTM as it processes a monitored BC-to-RT message

in the Monitor mode. DMA operations will vary slightly

depending on the type of message (i.e., RT-to-BC, RT-toRT,

etc.) It is assumed that the user has already written a "1" to

COMMAND BLOCK #1

CONTROL WORD

Figure 19. Monitor Command Block

Tail Pointers

CONTROL WORD

76543210

89101112131415

TT7 TT6 TT5 TT4 TT3 TT2 TT1 TT0

X X XCBA ME IOA BA/B X

B0 - B7 Time Tag (64µs resolution)

B8 - B11 Not Used

B12 - Bus A/B: Defines which of the dual redundant 1553 buses on which the BCRTM received

this message

B13 - IWA: Interrupt When Addressed. The BCRTM issues a standard priority interrupt

when the monitor accesses this Bus Monitor Command block.

B14 - ME: Message Error. The BCRTM sets this bit if a 1553 message error occurred while

receiving this message.

B15 - CBA: Command Block Activated. The BCRTM sets this bit when this Bus Monitor

Command Block is accessed by the BCRTM.

Figure 20: Bus Monitor Control/Status Word

BCRTM-36

state to enable Monitor operation.

Valid Command Received.

COMSTR goes active

•DMA Command Block Read. After receiving

a valid command, the BCRTM initiates a burst

DMA:

DMA arbitration (BURST)

Control Word read

Command Word Write

Data List Pointer read

Data Received.

•Data Word DMA.

The BCRTM initiates a DMA cycle for each Data

Word to store the data in memory, whether the

command was a transmit or receive command to any

valid monitored RT Address.

DMA arbitration

Data Word write (starting at Data List Pointer

address, incremented for each successive

word)

Status Word Received.

•Status Word DMA.

DMA arbitration

Status Word write.

Exception Handling.

If an interrupting condition occurs during the

message, the following occurs:

For High-Priority Interrupts:

HPINT is asserted (if enabled in Register 7).

For message errors, the BCRTM is put in a

hold state until the interrupt is acknowledged

(by writing a “1” to the appropriate bit in

For Standard Interrupts:

DMA arbitration (BURST)

Interrupt Status Word write

Command Block Pointer write

Tail Pointer read (into Register 6)

STDINTP pulses low

STDINTL asserted (if enabled)

Processing continues

Message Completion

Upon completion of the message, the BCRTM initiates

a DMA cycle to update the status word and fetch the

address of the next Monitor Command block:

DMA arbitration (BURST)

Control/ Status Word write

Tail Pointer write

9.0 EXCEPTION HANDLING AND

INTERRUPT LOGGING

The exception handling scheme the BCRTM uses is based

on an interrupt structure and provides a high degree of

flexibility in:

•defining the events that cause an interrupt,

•selecting between High-Priority and Standard

interrupts, and

•selecting the amount of interrupt history retained.

The interrupt structure consists of internal registers that

enable interrupt generation, control bits in the RT and BC

data structures (see the Remote Terminal Descriptor

Definition section, page 23, and the Bus Controller

Command Block definition, page 31), and an Interrupt Log

List that sequentially stores an interrupt events record in

system memory.

The BCRTM generates the Interrupt Log List (see figure

21) to allow the host CPU to view the Standard Interrupt

occurrences in chronological order. Each Interrupt Log List

entry contains three words. The first, the Interrupt Status

Word, indicates the type of interrupt (entries are only for

interrupts enabled). In the BC mode, the second word is a

Command Block Pointer that refers to the corresponding

Command Block. In the RT mode, the second word is a

Descriptor Pointer that refers to the corresponding

subaddress descriptor. The CPU-initialized third word, a

Tail Pointer, is read by the BCRTM to determine the next

Interrupt Log List address. The list length can be as long or

as short as required. The configuration of the Tail Pointers

determines the list length.

The host CPU initializes the list by setting the tail pointers.

This gives flexibility in the list capacity and the ability to

link the list around noncontagious blocks of memory. The

host CPU sets the list’s starting address using the Interrupt

Log List Register. The BCRTM then updates this register

with the address of the next list entry.

The internal High-Priority Interrupt Status/Reset Register

indicates the cause of a High-Priority Interrupt. The High-

Priority Interrupt signal is reset by writing a “1” to the set

bits in this register.

BCRTM-37

The interrupt structure also uses three BCRTM- driven output

signals to indicate when an interrupt event occurs:

STDINTL Standard Interrupt Level. This signal is

asserted when one or more of the events

enabled in the Standard Interrupt Enable

the Standard Interrupt bit in the High-Priority

Interrupt Status/Reset Register.

STDINTP Standard Interrupt Pulse. This signal is

pulsed for each occurrence of an event

enabled in the Standard Interrupt

Enable Register.

HPINT High-Priority Interrupt. This signal is

asserted for each occurrence of an event

enabled in the High-Priority Interrupt/Enable

the High-Priority Status/Reset Register

resets it.

Interrupt Status Word Definition

All bits in the Interrupt Status Word are active high and have the following functions:

Bit

Number Description

BIT 15 Interrupt Status Word Accessed. The BCRT always sets this bit during the DMA Write of the Interrupt.

Status Word. If the CPU resets this bit after reading the Interrupt Status Word, the bit can help the CPU determine

which entries have been acknowledged.

BIT 14 No Response Time-Out (Message Error condition). Further defines the Message Error condition to indicate that a

Response Time-Out condition has occurred.

BIT 13 (RT) Message Error (ME). Indicates the ME bit was set in the 1553 status word response.

BITs 12-8 Reserved.

BIT 7 (RT) Subaddress Event or Mode Code with Data Word Interrupt. Indicates a descriptor control word has been

accessed with either an Interrupt Upon Valid Command Received bit set or an Interrupt when Index=0 bit set (and

the Index is decremented to 0).

BIT 6 (RT) Mode Code without Data Word Interrupt. Indicates a mode code has occurred with an Interrupt When

Addressed interrupt enabled.

BIT 5 (RT) Illegal Broadcast Command. Applies to receive commands only. This bit indicates that a received command,

due to an illegal mode code or subaddress field, has been received in the broadcast mode. This does not include

invalid commands.

BIT 4 (RT) Illegal Command. This indicates that an illegal command has occurred due to an illegal mode code or

subaddress and T/R field. This does not include invalid commands.

BIT 3 (BC) Polling Comparison Match. Indicates a polling comparison interrupt.

BIT 2 (BC) Retry Fail. Indicates all the programmed retries have failed.

BIT 1 (BC, RT) Message Error. Indicates a Message Error has occurred.

BIT 0 (BC) Interrupt and Continue. This corresponds to the interrupt and continue function described in the Command

Block.

Figure 21. Interrupt Log List

ENTRY #3

ENTRY #2

ENTRY #1

TAIL POINTER

COMMAND BLOCK

INTERRUPT STATUS

POINTER REGISTER

INTERRUPT LOG LIST

POINTER

WORD

SUBADDRESS/MODE

CODE DESCRIPTOR

POINTER

BCRTM-38

Figure 22. Bus Controller Scenario

RTI 2RTI 2RTI 2RTI 2**

STATUSDATA 4DATA 3DATA 2DATA 1STATUSCMD #2CMD #1 RTI 2RTI 1BCBC

STATUSDATA 4DATA 3DATA 2DATA1STATUSCMD #2CMD #1 RTI 2RTI 1BCBC

MANCHESTER

DATA BUS A

MANCHESTER

DATA BUS B

INTERRUPT

ACTIVITY

BCRTM

ACTIVITY

DESCRIPTION

RTI 2RTI 2RTI 2RTI 2

BCRTM DMA

AUTO RETRY

DESCRIPTION

ACTIVITY

BCRTM

ACTIVITY

BCRTM DMA

INTERRUPT

DATA BUS B

MANCHESTER

DATA BUS A

MANCHESTERBC RTIBCBC

CMD DATA1DATA 2STATUS

TIME OUT TO 400 S

FETCH TAIL POINTER

STORE STATUS WORD #2

STORE DATA WORD#4

STORE DATA WORD #3

STORE DATA WORD#2

STORE DATA WORD#1

STORE STATUS WORD #1

FETCH COMMAND WORD #2

FETCH DATA POINTER

FETCH COMMAND WORD #1

FETCH CONTROL WORD

READ LOG LIST TAIL PTR

STORE CMD BLOCKPTR

STORE INTERRUPT STATUS WORD

RECOGNIZE ME BIT

STORE STATUS WORD #2

STORE DATA WORD#4

STORE DATA WORD#3

STORE DATA WORD #2

STORE DATA WORD#1

STORE STATUS WORD #1

FETCH COMMAND WORD #2

FETCH DATA POINTER

FETCH COMMAND WORD #1

FETCH CONTROL WORD

START BCRTM

INITIALIZE REGISTERS

SO STOP BCRTM

EOL IN CONTROL WORD

STORE INTERRUPT STATUS WORD

FETCH DATA WORD #2

FETCH DATA WORD#1

FETCH DATA POINTER

FETCH COMMAND WORD

FETCH CONTROL WORD

TIME OUT TO 400 s

Notes:

1. Times for DMA Arbitration and BCRTM DMA Activities are not shown to scale

relative to the 1553B message word lengths. This is done to illustrate the operation

of these signals.

2. * = response time of 4 to 12µs.

3. DMA Arbitration represents the DMAR↓ to DMACK↑ sequence.

4. The scenario assumes that all DMA grants (DMAG) are received in the required

period of time.

5. These times depend on the DMAG response time.

0µs168 to 175 to

484 to

492µs

400µs

344 to

392µs

400µs

BCRTM DMA

ARBITRATION3

BCRTM DMA

ARBITRATION3

BCRTM-39

12345678910 11 12 13 14 15 16 17 18 19 20

5 1 5 5 1

RESERVED

REMOTE TERMINAL

ADDRESS

SYNC

STATUS WORD

DATA WORD

SYNC

DATA P

REMOTE TERMINAL

ADDRESS T/R SUBADDRESS/

MODE DATA WORD

COUNT/MODE CODE

BIT TIMES

COMMAND WORD

MESSAGE ERROR

INSTRUMENTATION

SERVICE REQUEST

BROADCAST COMMANDRECEIVED

BUSY

SUBSYSTEM FLAG

DYNAMIC BUS CONTROL ACCEPTANCE

TERMINAL FLAG

PARITY

Note:

T/R - transmit/receive

P - parity

Figure 23. MIL-STD-1553B Word Formats

BCRTM-40

10.0 ABOSOLUTE MAXIMUM RATINGS*

(REFERENCED TO VSS)

RECOMMENDED OPERATING CONDITIONS

SYMBOL PARAMETER LIMITS UNIT

DC supply voltage

Temperature range

Operating frequency MHz

VDD

12 ±.01%

4.5 to 5.5

-55 to +125

SYMBOL PARAMETER LIMITS UNIT

DC supply voltage

Voltage on any pin

DC input current

Storage temperature

Notes:

Maximum junction temperature °

1. Does not reflect the added PD due to an output short-circuited.

* Stresses outside the listed absolute maximum ratings may cause permanent damage to the device. This is a stress rating only, and

functional operation of the device at these or any other conditions beyond limits indicated in the operational sections of this specification

is not recommended. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

ΘThermal resistance, junction-to-case C/Watt

VDD

VI/O

TSTG

TJMAX

Average power dissipation 1

-0.3 to + 7.0

-0.3 to VDD + 0.3

± 10

-65 to + 150

+ 175

300

BCRTM-41

11.0 DC ELECTRICAL CHARACTERISTICS

(VDD = 5.0V ± 10%; -55°C < TC < + 125°C)

Notes:

1. Supplied as a design limit, but not guaranteed or tested.

2. Not more than one output may be shorted at a time for a maximum duration of one second.

3. Measured only for initial qualification, and after process or design changes which may affect input/output capacitance.

4. Includes current through input pull-up. Instantaneous surge currents on the order of 1 ampere can occur during output switching.

Voltage supply should be adequately sized and decoupled to handle a large current surge.

5. All inputs with internal pull-ups should be left floating. All other inputs should be tied high or low.

6. Functional tests are conducted in accordance with MIL-STD-883 with the following input test conditions

VIH = VIH(min) +20%, -0%; VIL = VIL(max) +0%, -50%, as specified herein, for TTL-compatible inputs.

Devices may be tested using input voltage within the above specified range, but are guaranteed to VIH(min) and VIL(max).

7. To 1.0E6 total dose; above this level, CMOS I/Os required.

8. Guaranteed to pre- and post-irradiation limits.

SYMBOL PARAMETER CONDITION MINIMUM MAXIMUM UNIT

VIL

Rad and

Non-Rad

Low-level input voltage

TTL inputs 0.8 V

VIH

Non-Rad High-level input voltage

TTL inputs 2.0 V

VIH

Rad-Hard High-level input voltage 6

TTL inputs 72.2 V

IIN

Non-Rad Input leakage current

TTL inputs

Inputs with pull-up resistors

VIN = VDD or VSS

VIN = VDD

VIN = VSS

-1

-550

-1

-80

µA

IIN

Rad-Hard Input leakage current

TTL7

Inputs with pull-up resistors

VIN = VDD or VSS

VIN = VDD

VIN = VSS

-10

-900

-150

µA

VOL1Low-level output voltage

TTL outputs IOL = 3.2mA 0.4 V

VOH1High-level output voltage

TTL outputs IOH = -400µA2.4 V

IOZ Three-state output leakage current

TTL outputs VO = VDD or VSS -10 10 µA

IOS Short-circuit output current 1, 2 VDD = 5.5V, VO = VDD

VDD = 5.5V, VO = 0V -110 110 mA

CIN Input capacitance 3ƒ = 1MHz @ 0V 10 pF

COUT Output capacitance 3ƒ = 1MHz @ 0V 15 pF

CIO Bidirect I/O capacitance 3ƒ = 1MHz @ 0V 20 pF

IDD Average operating current 1, 4 ƒ = 12MHz, CL = 50pF 50 mA

QIDD Quiescent current8See Note 5, Tc = +125oC

Tc = 25oC, -55oC1

35 mA

µA

BCRTM-42

12.0 AC ELECTRICAL CHARACTERISTICS

(OVER RECOMMENDED OPERATING CONDITIONS)

PARAMETERSYMBOL

BUS

OUTPUT

OUT-OF-PHASE

OUTPUT

IN-PHASE

INPUT

Notes:

1. Timing measurements made at (VIH MIN + VIL MAX)/2.

2. Timing measurements made at (VOL MAX + VOH MIN)/2.

3. Based on 50pF load.

4. Unless otherwise noted, all AC electrical characteristics are guaranteed by design or characterization.

1 1

VIH

VIL MAX VIH MIN

VIL MAX

VOH MIN

VOL MAX

VOH MIN

VOL MAX

VOH MIN

VOL MAX

tatb

tgth

INPUT↑ to response↑

INPUT↓ to response↓

INPUT↑ to response↓

INPUT↓ to response↑

INPUT↓ to data valid

INPUT↓ to high Z

INPUT↑ to high Z

INPUT↑ to data valid

90%

Figure 25. AC Test Loads and Input Waveforms

Note:

50pF including scope probe and test socket

Input Pulses

10%10%

90%

< 2ns < 2ns

50pF

•

IREF (source)

IREF (sink)

VREF

Output Loading

Figure 24. Typical Timing Measurements

BCRTM-43

MCLKD2

ADDRESS

DATA

AEN

BURST

DMA GRANT RECOGNIZED ON THIS EDGE

THMC1+10

SYMBOL PARAMETER MIN MAX UNITS

-2

THMC1-10

MCLK-20

2x-2MCLK

MCLK

4xMCLK

6xMCLK

MCLK+20

3.5 (1.9)

MCLK = period of the memory clock cycle.

BURST signal is for multiple-word DMA accesses.

THMC1 is equivalent to the positive phase of MCLK (see figure 27).

-10 ns10 s

01.9 (0.8) µ

-5

DMAR

DMAG

DMACK

TSCTL

MEMCSO

tSHL1

tPW2

tOOZL1

tPHL4

tPHL1

tPHL2

tPZL1

tPHL3

RWR/RRD2

tSHL16DMACK↓ to DMAR High Impedance RAD

NON-RAD

DMAG↓ to DMACK↓ 3

DMAG↓ to TSCTL↓

TSCTL↓ to ADDRESS valid RAD

NON-RAD

RWR/RRD↑ to DMACK↑

TSCTL↓ to RWR/RRD↓

DMAG↓ to DMAG↑

DMAR↓ to BURST↑

DMAR↓ to DMAG↓ 5

DMAR↓ to DMAG↓ 4

Notes:

1. Guaranteed by test.

2. See figures 27 & 28 for detailed DMA read and write timing.

3. DMAG must be asserted at least 45ns prior to the rising edge of MCLKD2 in order to be recognized for the next MCLKD2 cycle.

If DMAG is not asserted at least 45ns prior to the rising edge of MCLKD2, DMAG is not recognized until the following MCL

KD2 cycle.

4. Provided MCLK = 12MHz. Number in parentheses indicates the longest DMAR↓ to DMAG↓ allowed during worst-case bus switching conditions

in order to meet MIL-STD-1553B RT Response Time. The number not in parentheses applies to all other circumstances.

5. Provided MCLK = 6MHz. Number in parentheses indicates the longest DMAR↓ DMAG↓ allowed during worst-case bus switching conditions

in order to meet MIL-STD-1553B RT Response Time. The number not in parentheses applies to all other circumstances.

6. Tested only at initial qualification, and after any design or process changes which may affect this characteristic.

tPHL1

tPHL21

tPZL16

tHLH2

tPHL3

tPW21

tOOZL1

tPHL4

tHLH2

Figure 26. BURST DMA Timing

BCRTM-44

400

THMC1+10

MCLK-10

(DATA hold)

)

UNITSMAXMINPARAMETERSYMBOL

DATA

ADDRESS

MCLKD2

MCLK

MCLK+5

THMC1+10

THMC1 THMC2

600

1. Guaranteed by test.

Note:

400

tSHL12

tSLHI

tHLZ2

tHLZ

tPW1

tPLH2

tIOHL1 1

tPLH1 1

ADDRESS valid to RRD↓ (ADDRESS set-up) RAD

NON-RAD

RRD↓ to RRD↑

RRD↑ to DATA High Impedance

RRD↑ to ADDRESS High Impedance

MCLK↑ to MCLKD2↑

MCLK↑ to TSCTL/MEMCSO↓

MCLK↑ to RRD↓

DATA valid to RRD↑ (DATA set-up)

(ADDRESS hold)

TSCTL

MEMCSO

RRD

tPLH1

IOHL1

tPLH2

tSHL1

tSLH1

tHLZ1

tHLZ2

Figure 27. BCRTM DMA Read Timing (One-Word Read)

2. Pre- and Post-Irradiation Limits.

10 10

-5 +5

BCRTM-45

400

MCLK-10

THMC1-10

THMC2-10

(ADDRESS hold)

(ADDRESS setup)

UNITSMAXMINPARAMETERSYMBOL

DATA

ADDRESS

MCLKD2

MCLK

THMC2+5

THMC1+10

MCLK+5

THMC1 THMC2

600

1. Guaranteed by test

Note:

400

tSHL12

tPW1

tHLZ2

tHLZ1

tOOZL11,2

tPLH2

tIOHL1 1

tPLH1 1

ADDRESS valid to RWR↓

RWR↓ to DATA valid NON-RAD

RAD

RWR↑ to ADDRESS High Impedance

RWR↑ to DATA High Impedance

MCLK↑ to MCLKD2↑

MCLK↑ to TSCTL/MEMCSO↓

MCLK↑ to RWR↓

RWR↓ to RWR↑

(DATA hold)

TSCTL

MEMCSO

RWR

tPLH1

IOHL1

tPLH2

tSHL1 tOOZL1 tPW1

tHLZ1

tHLZ2

Figure 28. BCRTM DMA Write Timing (One-Word Write)

-5 30

2. Pre- and Post-Irradiation Limits.

BCRTM-46

(DATA hold)

(ADDRESS hold)

UNITSMAXMINPARAMETERSYMBOL

ADDRESS

DATA

(DATA access)

Notes:

1. Guaranteed by functional test.

2. User must adhere to both tOOZH1 and tOOZH2 timing constraints to ensure valid data.

tHLH2 RD+CS↑ to DATA High Impedance

tOOZH22

tOOZH1 2

tHLH1

tPW1

tPW21

ADDRESS valid to DATA valid

RD+CS↓ to DATA Valid

RD+CS↑ to ADDRESS High Impedance

RD+CS↓ to RD+CS↑

RD+CS↑ to RD+CS↓

RD+CS

tOOZH2tOOZH1 tHLH1

tHLH2

tPW1 tPW2

(DATA hold)

(ADDRESS hold)

(ADDRESS setup) UNITSMAXMINPARAMETERSYMBOL

ADDRESS

DATA

(DATA setup) 60

tHLH2 WR+CS↑ to ADDRESS High Impedance

tPW21WR+CS↑ to WR+CS↓

tHLH1 WR+CS↑ to DATA High Impedance

tPW1 WR+CS↓ to WR+CS↑

tSHL2 DATA valid to WR+CS ↓

tSHL1 ADDRESS valid to WR+CS↓

WR+CS

tSHL1 tPW1 tHLH2

tHLH1 tPW2

Figure 29. BCRTM Register Read Timing

Figure 30. BCRTM Register Write Timing

tSHL2

Note:

1. Guaranteed by functional test.

BCRTM-47

SYMBOL PARAMETER MIN MAX UNITS

MANCHESTER

DMA

ACTIVITY

C D D

Data word to DMA activity 4µs

Note:

1. The pulse width = (11µs -tDMA -tPZL1) where tDMA is the time to complete DMA activity (i.e., DMAR↓ to DMACK↑).

2. Guaranteed by functional test.

tPZL11,2

tPZLI

This diagram indicates the relationship between the incoming Manchester code and DMA activity (i.e., DMAR↓ to DMACK↑).

UNITSMAXMINPARAMETERSYMBOL 0

0ns

tPHL1 1RD↓ to RRD↓

tPLH2 1

tPHL3 1WR↓ to RWR↓

MEMCSI↓ to MEMCSO↓

tPHL1

tPHL2

tPHL3

RRD

RWR

MEMCSI

MEMCSO

Figure 31. BCRTM Dual-Port Interface Timing Delays

Figure 32. DMA Activity Memory Window (RT Mode)

BCRTM-48

5ns

UNITSMAXMINPARAMETERSYMBOL

-5

0ns

MCLK

MCLKD2

Notes:

1. When DMAG is asserted before DMAR, the DMAG signal passes through the BCRTM as DMAGO.

2. Pre- and Post-Irradiation Limits.

tPLH2

DMAG↓ to DMAGO ↓

tSHL12

tPHL11

DMACK↓ to DMAR High Impedance RAD

NON-RAD

MCLK↑ to MCLKD2↑

DMAR

DMAG

DMAGO

DMACK

tPLH2

tPHL1 tSHL1

Figure 33. BCRTM Arbitration when DMAG is Asserted before Arbitration

010

Packaging-1

Package Selection Guide

NOTE:

1. 84LCC package is not available radiation-hardened.

Product

RTI RTMP RTR BCRT BCRTM BCRTMP RTS XCVR

24-pin DIP

(single cavity) X

36-pin DIP

(dual cavity) X

68-pin PGA X X

84-pin PGA X X X X1

144-pin PGA X

84-lead LCC X X X1

36-lead FP

(dual cavity)

(50-mil ctr)

84-lead FP X X

132-lead FP X X

Packaging-2

144-Pin Pingrid Array

1.565 ± 0.025

-B-

1.565 ± 0.025 -A-

0.080 REF.

(2 Places)

0.040 REF.

0.100 REF.

(4 Places)

0.130 MAX.

0.050 ± 0.010 A

0.130 ±0.010

PIN 1 I.D.

(Geometry Optional) -C-

(Base Plane)

0.018 ± 0.002

0.030

0.010 CA B

SIDE VIEW

TOP VIEW

0.003 MIN. TYP.

D1/E1

1.400

0.100

TYP.

PIN 1 I.D.

(Geometry Optional)

D1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Notes:

1. True position applies to pins at base plane (datum C).

2. True position applies at pin tips.

3. All package finishes are per MIL-M-38510.

4. Letter designations are for cross-reference to MIL-M-38510.

BOTTOM VIEW

Packaging-3

132-Lead Flatpack (25-MIL Lead Spacing)

SIDE VIEW

TOP VIEW

BOTTOM VIEW A-A

DETAIL A

0.018 MAX. REF.

0.014 MAX. REF.

(At Braze Pads)

0.250

MIN.

REF.

LEAD KOVAR

SEE DETAIL A A

0.005 + 0.002

- 0.001

0.110

0.006

D1/E1

0.950 ± 0.015 SQ.

D/E

1.525 ± 0.015 SQ.

PIN 1 I.D.

(Geometry

Optional)

0.025

Notes:

1. All package finishes are per MIL-M-38510.

2. Letter designations are for cross-reference to MIL-M-38510.

0.005 MIN. TYP.

Packaging-4

84-LCC

SIDE VIEW

TOP VIEW

BOTTOM VIEW A-A

Notes:

1. All package finishes are per MIL-M-38510.

2. Letter designations are for cross-reference to MIL-M-38510.

L/L1

0.050 ± 0.005 TYP.

0.025 ± 0.003

0.050

0.015 MIN.

PIN 1 I.D.

(Geometry Optional)

0.020 X 455 REF.

0.040 x 45_

REF. (3 Places)

D/E

1.150 ± 0.015 SQ.

0.115 MAX.

0.080 ± 0.008 A

PIN 1 I.D.

(Geometry Optional)

Packaging-5

84-Lead Flatpack (50-MIL Lead Spacing)

SIDE VIEW

TOP VIEW

BOTTOM VIEW A-A

D/E

1.810 ± 0.015 SQ.

Notes:

1. All package finishes are per MIL-M-38510.

2. Letter designations are for cross-reference to MIL-M-38510.

DETAIL A

D1/E1

1.150 ± 0.012 SQ.

0.110

0.060

0.007 ± 0.001

LEAD KOVAR

SEE DETAIL A

PIN 1 I.D.

(Geometry

Optional)

0.016 ± 0.002

0.260

MIN.

REF.

0.005 MIN. TYP.

0.050

0.014 MAX.

REF.

(At Braze Pads)

0.018 MAX. REF.

Packaging-6

84-Pin Pingrid Array

SIDE VIEW

TOP VIEW

BOTTOM VIEW A-A

1.100 ± 0.020

-B-

-A- A

0.130 MAX.

0.050 ± 0.010

0.130 ± 0.010

-C-

(Base Plane) b

0.018 ± 0.002

PIN 1 I.D.

(Geometry Optional)

1.000

D1/

0.100

TYP.

0.003 MIN.

1 2 3 4 5 6 7 8 9 10 11

Notes:

1. True position applies to pins at base plane (datum C).

2. True position applies at pin tips.

3. All packages finishes are per MIL-M-38510.

4. Letter designations are for cross-reference to MIL-M-38510.

PIN 1 I.D.

(Geometry Optional)

0.030

0.010 CA B

Packaging-7

SIDE VIEW

TOP

BOTTOM VIEW A-A

1.100 ± 0.020

PIN 1 I.D.

(Geometry Optional)

1 2 3 4 5 6 7 8 9 10 11

Notes:

1True position applies to pins at base plane (datum C).

2True position applies at pin tips.

3. All packages finishes are per MIL-M-38510.

4. Letter designations are for cross-reference to MIL-M-38510.

PIN 1 I.D.

(Geometry Optional)

D1/E1

1.00

0.003 MIN. TYP.

0.100

TYP.

0.130 MAX.

0.050 ± 0.010

0.130 ± 0.010A

-A-

-B-

1.100 ± 0.020

-C-

(Base Plane)

68-Pin Pingrid Array

0.030

0.010 CAB1

∅

0.010 ± 0.002

Packaging-8

1.800 ± 0.025

36-Lead Flatpack, Dual Cavity (100-MIL Lead Spacing)

TOP VIEW

END VIEW

0.750 ± 0.015

Notes:

1All package finishes are per MIL-M-38510.

2. It is recommended that package ceramic be mounted to

a heat removal rail located on the printed circuit board.

A thermally conductive material such as MERECO XLN-589 or

equivalent should be used.

3. Letter designations are for cross-reference to MIL-M-38510.

PIN 1 I.D.

(Geometry Optional)

0.490

MIN.

0.015 ± 0.002

0.10

0.008 + 0.002

- 0.001

0.080 ± 0.010

(At Ceramic Body)

0.130 MAX.

Packaging-9

36-Lead Flatpack, Dual Cavity (50-MIL Lead Spacing)

TOP

0.700 + 0.015

Notes:

1. All package finishes are per MIL-M-38510.

2. It is recommended that package ceramic be mounted to

a heat removal rail located on the printed circuit board.

A thermally conductive material such as MERECO XLN-589

or equivalent should be used.

3. Letter designations are for cross-reference to MIL-M-38510.

0.007+ 0.002

- 0.001

0.070 + 0.010

(At Ceramic Body)

0.100 MAX.

END

1.000 ± 0.025

0.016 + 0.002

0.050

PIN 1 I.D

(Geometry Optional)

0.330

MIN.

Packaging-10

36-Lead Side-Brazed DIP, Dual Cavity

TOP VIEW

END VIEW

0.590 ± 0.012

Notes:

1. All package finishes are per MIL-M-38510.

2. It is recommended that package ceramic be mounted to

a heat removal rail located on the printed circuit board.

A thermally conductive material such as MERECO XLN-589

or equivalent should be used.

3. Letter designations are for cross-reference to MIL-M-38510.

PIN 1 I.D.

(Geometry Optional)

SIDE VIEW

0.005 MIN.

1.800 ± 0.025

0.005 MAX. e

0.100

0.155 MAX. L/L1

0.150 MIN.

0.010 + 0.002

- 0.001

0.600 + 0.010

(At Seating Plane)

0.018 ± 0.002

Packaging-11

0.590 ± 0.015 S1

0.005 MIN. S2

0.005 MAX.

TOP VIEW

PIN 1 I.D.

(Geometry Optional)

1.200 ± 0.025

SIDE VIEW

0.140 MAX. L/L1

0.150 MIN.

0.100

Notes:

1. All package finishes are per MIL-M-38510.

2. It is recommended that package ceramic be mounted to

a heat removal rail located on the printed circuit board.

A thermally conductive material such as MERECO XLN-589 or

equivalent should be used.

3. Letter designations are for cross-reference to MIL-M-38510.

END VIEW

0.010 + 0.002

- 0.001

0.600 + 0.010

(At Seating Plane)

0.018 ± 0.002

24-Lead Side-Brazed DIP, Dual Cavity

ORDERING INFORMATION

UT1553B BCRT/M Bus Controller/Remote Terminal/Monitor: SMD

Lead Finish:

(A) = Solder

(X) =Optional

Case Outline:

(X) =84 pin PGA (NonRad only)

(Y) =84 pin FP

(Z) =84 pin LCC (NonRad only)

Class Designator:

(-) =Blank or No field is QML Q

(V) = Class V

Drawing Number: 8957701

Total Dose:

(F) = 3E5 (300KRad)

(G) = 5E5 (500KRad)

(H) = 1E6 (1MRad)

(R) = 1E5 (100KRad)

(-) = None

Federal Stock Class Designator: No options

5962 * * * * *

Notes:

1. Lead finish (A, C, or X) must be specified.

2. If an "X" is specified when ordering, part marking will match the lead finish and will be either "A" (solder) or "C" (gold).

3. For QML Q product, the Q designator is intentionally left blank in the SMD number (e.g. 5962-89577Q1YX).

4. 84 LCC only available with solder lead finish.

UT1553B BCRT/M Bus Controller/Remote Terminal/Monitor

Total Dose:

() =None

Lead Finish:

(A) =Solder

(X) =Optional

Screening:

(P) =Prototype

Package Type:

(A) =84pin LCC (solder only)

(G) =84 pin PGA

(W) =84 pin FP

UTMC Core Part Number

UT1553B/

BCRTM- * * * *

Notes:

1. Lead finish (A, C, or X) must be specified.

2. If an "X" is specified when ordering, part marking will match the lead finish and will be either "A" (solder) or "C" (gold).

3. Mil Temp range flow per UTMC’s manufacturing flows document. Devices are tested at -55°C, room temperature, and 125°C. Radiation neither tested

nor guaranteed.

4. Prototpe flow per UTMC’s document manufacturing flows and are tested at 25°C only. Radiation characteristics neither tested nor guaranteed. Lead

finish is GOLD only.

5. 84 LCC only available with solder lead finish.