February 2014
IPUG92_01.3
MachXO2™ LPDDR SDRAM Controller IP Core User’s Guide
© 2014 Lattice Semiconductor Corp. All Lattice trademarks, registered trademarks, patents, and disclaimers are as listed at www.latticesemi.com/legal. All other brand
or product names are trademarks or registered trademarks of their respective holders. The specifications and information herein are subject to change without notice.
IPUG92_01.3, February 2014 2 LPDDR SDRAM Controller User’s Guide
Chapter 1. Introduction .......................................................................................................................... 4
Introduction ........................................................................................................................................................... 4
Quick Facts ........................................................................................................................................................... 4
Features ................................................................................................................................................................ 4
Chapter 2. Functional Description ........................................................................................................ 5
Overview ............................................................................................................................................................... 5
Initialization Block......................................................................................................................................... 5
Read Training Block..................................................................................................................................... 6
Data Control Block ....................................................................................................................................... 6
LPDDR I/Os ................................................................................................................................................. 6
Command Decode Logic Block.................................................................................................................... 6
Command Application Logic Block............................................................................................................... 6
Signal Descriptions ............................................................................................................................................... 6
Using the Local User Interface.............................................................................................................................. 9
Initialization and Training ............................................................................................................................. 9
Command and Address ............................................................................................................................. 10
User Commands ........................................................................................................................................ 11
Power Down and Deep Power Down......................................................................................................... 13
User Commands for Wishbone Interface ................................................................................................... 14
Local-to-Memory Address Mapping .................................................................................................................... 15
Mode Register Programming .............................................................................................................................. 15
Chapter 3. Parameter Settings ............................................................................................................ 16
Mode Tab ............................................................................................................................................................ 17
Type Tab ............................................................................................................................................................. 17
Select Memory ........................................................................................................................................... 17
Clock .......................................................................................................................................................... 17
Memory Data Bus Size .............................................................................................................................. 18
Clock Width ................................................................................................................................................ 18
Wishbone Bus ............................................................................................................................................ 18
Setting Tab.......................................................................................................................................................... 18
Row Size .................................................................................................................................................... 19
Column Size............................................................................................................................................... 19
Auto Refresh Burst Count .......................................................................................................................... 19
External Auto Refresh ................................................................................................................................ 19
Read Re-training ........................................................................................................................................ 19
Re-training Period ...................................................................................................................................... 19
Address Space for Training........................................................................................................................ 19
Read Data Auto Alignment......................................................................................................................... 19
Partial Array Self Refresh........................................................................................................................... 19
Memory Clock ............................................................................................................................................ 20
Burst Length............................................................................................................................................... 20
CAS Latency .............................................................................................................................................. 20
Burst Type.................................................................................................................................................. 20
Memory Device Timing Tab ................................................................................................................................ 21
Manually Adjust.......................................................................................................................................... 21
tCLK – Memory Clock ................................................................................................................................ 21
Synthesis and Simulation Tab............................................................................................................................. 22
Support Synplify ......................................................................................................................................... 22
Support LSE............................................................................................................................................... 22
Table of Contents
Table of Contents
IPUG92_01.3, February 2014 3 LPDDR SDRAM Controller User’s Guide
Support ModelSim...................................................................................................................................... 22
Support Active HDL.................................................................................................................................... 22
Core Synthesis with Lattice LSE ................................................................................................................ 22
Info Tab ............................................................................................................................................................... 23
Memory I/F Pins ......................................................................................................................................... 23
User I/F Pins .............................................................................................................................................. 23
Getting Started .................................................................................................................................................... 24
Chapter 4. IP Core Generation............................................................................................................. 24
IPexpress-Created Files and Top Level Directory Structure............................................................................... 26
LPDDR SDRAM Controller IP Core File Structure.............................................................................................. 26
Top-level Wrapper...................................................................................................................................... 27
Obfuscated Module for the Core and I/O Modules..................................................................................... 27
Simulation Files for IP Core Evaluation............................................................................................................... 28
Test Bench Top.......................................................................................................................................... 28
Obfuscated Core and I/O Simulation Models............................................................................................. 28
Command Generator ................................................................................................................................. 28
Monitor ....................................................................................................................................................... 28
Memory Model ........................................................................................................................................... 28
Memory Model Parameter.......................................................................................................................... 29
Evaluation Script File ................................................................................................................................. 29
Instantiating the Core .......................................................................................................................................... 29
Running Functional Simulation ........................................................................................................................... 29
Synthesizing and Implementing the Core in a Top-Level Design ....................................................................... 30
Hardware Evaluation........................................................................................................................................... 30
Enabling Hardware Evaluation................................................................................................................... 30
Updating/Regenerating the IP Core .................................................................................................................... 30
Regenerating an IP Core ........................................................................................................................... 30
Chapter 5. Application Support........................................................................................................... 32
Core Implementation........................................................................................................................................... 32
Understanding Preferences ................................................................................................................................ 32
Chapter 6. Core Verification ................................................................................................................ 33
Chapter 7. Support Resources ............................................................................................................ 34
Lattice Technical Support.................................................................................................................................... 34
E-mail Support ........................................................................................................................................... 34
Local Support ............................................................................................................................................. 34
Internet ....................................................................................................................................................... 34
References.......................................................................................................................................................... 34
JEDEC Web Site................................................................................................................................................. 34
Revision History .................................................................................................................................................. 34
Appendix A. Resource Utilization ....................................................................................................... 35
MachXO2 Devices .............................................................................................................................................. 35
Ordering Part Number......................................................................................................................................... 35
IPUG92_01.3, February 2014 4 LPDDR SDRAM Controller User’s Guide
Introduction
The LPDDR Synchronous Dynamic Random Access Memory (SDRAM) Controller is a general-purpose memory
controller that interfaces with industry standard LPDDR memory devices/modules compliant with JESD209B,
LPDDR SDRAM Standard, and provides a generic command interface to user applications. This IP core reduces
the effort required to integrate the LPDDR memory controller with the remainder of the application and minimizes
the need to directly deal with the LPDDR memory interface.
Quick Facts
Table 1-1 gives quick facts about the LPDDR SDRAM Controller IP core for MachXO2™ devices.
Table 1-1. LPDDR SDRAM Controller IP Core Quick Facts
Features
• Interfaces to industry standard LPDDR SDRAM devices compliant to JESD209B
• Double-data rate architecture: two data transfers per clock cycle
• Bi-directional data strobe per byte of data (DQS)
• Programmable auto refresh support
• Data mask support – one mask per byte
• Power-down and deep-power-down support
• Power-on initialization support
• Re-initialization after a deep-power-down support
• Dynamic I/O training after initialization
• Periodic I/O retraining after an auto-refresh burst
• Dynamic memory clock power off during self refresh, power-down and deep-power-down operations
• Single-port operation support
• Full, half and quarter array self refresh support
• Status register read support
• TCSR programmability through MRS
LPDDR IP Configuration
16-bit, Generic 8-bit, Generic 16-bit, Wishbone 8-bit, Wishbone
Core Requirements
FPGA Families Supported MachXO2
Minimum Device Needed LCMXO2-2000
CABGA256
LCMXO2-2000
TQFP144
LCMXO2-2000
CABGA256
LCMXO2-2000
CSBGA132
Resource Utilization Target Device LCMXO2-7000HE-6FG484C
LUTs 1684 1620 1523 1389
sysMEM EBRs 0 0 0
Registers 880 849 933 834
Design Tool Support
Lattice Implementation Lattice Diamond® 3.1
Synthesis Lattice Synthesis Engine (LSE)
Synopsys Synplify Pro® for Lattice I-2013.09L
Simulation Aldec Active-HDLTM 9.3 Lattice Edition
Mentor Graphics ModelSim® SE 6.6 or later
Chapter 1:
Introduction
IPUG92_01.3, February 2014 5 LPDDR SDRAM Controller User’s Guide
Overview
The LPDDR memory controller consists of two major parts: the controller core logic module and the I/O logic mod-
ule. This section briefly describes the operation of each of these modules. Figure 2-1 provides a high-level block
diagram illustrating the main functional blocks and the technology used to implement the LPDDR SDRAM Control-
ler IP core functions.
Figure 2-1. LPDDR SDRAM Controller Block Diagram
The core module has several functional sub-modules: Initialization Block, Command Decode Logic Block, Com-
mand Application Logic Block, Data Control Block and Read Training Block. LPDDR I/O module implements the
physical interface (PHY) to the memory device. This block mostly consists of MachXO2 device I/O primitives which
are compliant to LPDDR electrical and timing requirements.
Initialization Block
The Initialization Block performs the LPDDR memory initialization sequence as defined by the JEDEC protocol.
After power-on or a normal reset of the LPDDR controller, memory device must be initialized before any command
is sent to the controller. It is user’s responsibility to assert the init_start input to the LPDDR controller to start the
memory initialization sequence. The completion of initialization is indicated by the init_done output signal.
This module automatically re-initializes the memory device upon exiting a deep-power-down operation.
Command
Decode Logic
cmd
write_data
addr
data_mask
cmd_rdy
read_data
inti_done
data_rdy
Initialization
Command
Application
Logic
Data Control
LPDDR
I/Os
em_ddr_cke
em_ddr_we_n
em_ddr_ras_n
em_ddr_cas_n
em_ddr_addr
em_ddr_ba
em_ddr_dm
sysCLOCK PLL
clk_in
cmd_valid
init_start
read_data_valid3
Configuration Interface
tRC tRP tXP
em_ddr_data
em_ddr_dqs
em_ddr_clk
tSRR
em_ddr_cs_n
rst_n
rt_done1
sclk
ext_auto_ref_ack2
ext_auto_ref2
tRCD
Read
Training
rt_req1
rt_act
rt_err
1. Available when read re-training user control is enabled
2. Available when external auto-refresh is enabled
3. 2-bit bus if read data auto alignment is disabled
Chapter 2:
Functional Description
Functional Description
IPUG92_01.3, February 2014 6 LPDDR SDRAM Controller User’s Guide
Read Training Block
The Read Training Block adjusts the MachXO2 I/Os for write/read operations. It is automatically activated at the
end of an initialization sequence and at the end of every Nth auto refresh burst cycle where N is a user configurable
value to set a read re-training interval provided in IPexpress GUI. Alternatively, a user may choose to fully control
the timing of read re-training by selecting the Read Re-training User Control option from the GUI.
Data Control Block
The Data Control Block generates the control signals for the I/Os for write/read operations. This block implements
all the logic needed to ensure that the data write/read to and from the memory is transferred to the local user inter-
face in a deterministic and coherent manner.
LPDDR I/Os
The LPDDR I/O modules are MachXO2 device primitives that directly connect to the LPDDR memory. These prim-
itives implement all the interface signals required for memory access. They convert the single data rate (SDR) data
to double rate LPDDR data for write operations and perform the LPDDR to SDR conversion in read mode.
Command Decode Logic Block
The Command Decode Logic (CDL) Block accepts user commands from the local interface and decodes them to
generate a sequence of internal memory commands depending on the current command and the status of current
bank and row. It tracks the open/close status of every bank and stores the row address of every open bank. The
controller implements a command pipeline enabling the next command in the queue to be decoded while the cur-
rent command is presented at the memory interface.
Command Application Logic Block
The Command Application Logic (CAL) Block accepts and processes the internal command sequences from the
Command Decode Logic. It translates each sequence into memory commands that comply with the JEDEC proto-
col sequences and timing requirements of the LPDDR memory device. It is the module responsible for protocol
compliance.
Signal Descriptions
Table 2-1 describes the user interface signals at the top level.
Table 2-1. LPDDR SDRAM Memory Controller Top-Level I/O List for Generic Interface
Port Name Active State I/O Description
Local User Interface
clk_in N/A Input Reference clock. It is connected to the PLL input.
rst_n Low Input Asynchronous reset. It resets the entire IP core when
asserted.
init_start High Input
Initialization start request. Should be asserted to initiate
memory initialization either right after the power-on reset or
before sending the first user command to the memory con-
troller
cmd[3:0] N/A Input User command input to the memory controller.
cmd_valid High Input Command and address valid input. When asserted, the addr
and cmd inputs are valid.
addr[ADDR_WIDTH-1:0] N/A Input User read or write address input to the memory controller.
write_data[DSIZE-1:0] N/A Input Write data input from user logic to the memory controller. The
user side write data width is two times the memory data bus
data_mask[(DSIZE/8)-1:0] N/A Input Data mask input for write_data.
rt_req High Input Read training request. Available when the read re-training
user control option is enabled. When asserted, the core is
requested to perform read training.
Functional Description
IPUG92_01.3, February 2014 7 LPDDR SDRAM Controller User’s Guide
rt_err High Output Read training error output. When asserted, it indicates that
the read training process has been failed.
sclk N/A Output System clock output. The user logic uses this as a system
clock unless an external clock generator is used.
init_done High Output Initialization done output. It is asserted for one clock cycle
when the core completes the memory initialization routine.
cmd_rdy High Output Command ready output. When asserted, it indicates the core
is ready to accept the next command and address.
data_rdy High Output Data ready output. When asserted, it indicates the core is
ready to receive the write data.
read_data[DSIZE-1:0] N/A Output Read data output from the memory to the user logic.
read_data_valid
[DQS_WIDTH-1:0]
/read_data_valid
High Output
Read data valid output. When asserted, it indicates the data
on the read_data bus is valid. Each bit is an independent out-
put of the corresponding DQS group when the read data
auto-alignment option is disabled. When enabled, the single-
bit read_data_valid validates the auto-aligned read data.
rt_done High Output
Read training done output. Available when the read re-train-
ing user control option is enabled. When asserted, the core
indicates that the requested read training has been com-
pleted.
rt_act High Output Read training active output. When asserted, it indicates that
the core is in the read training process.
ext_auto_ref High Input
User external auto refresh request. Available when the exter-
nal auto refresh option is enabled. When asserted, the core
is requested to perform an auto refresh burst.
ext_auto_ref_ack High Output
User external auto refresh acknowledge output. Available
when the external auto refresh option is enabled. When
asserted, the core indicates that the requested user auto-
refresh burst has been completed.
Table 2-1. LPDDR SDRAM Memory Controller Top-Level I/O List for Generic Interface (Continued)
Port Name Active State I/O Description
Functional Description
IPUG92_01.3, February 2014 8 LPDDR SDRAM Controller User’s Guide
Table 2-2 describes the user interface signals at the top level I/O for Wishbone Interface.
Table 2-2. LPDDR SDRAM Memory Controller Top-Level I/O List for Wishbone Interface
Port Name I/O Description
S0_ADR_I[31:0],
S1_ADR_I[31:0] Input
The address input array used to pass a binary address.
For LPDDR memory of:
2 G:
S0_ADR_I[26:0] = valid address
S0_ADR_I[31:27] = unused
1 G:
S0_ADR_I[25:0] = valid address
S0_ADR_I[31:26] = unused
512 M:
S0_ADR_I[24:0] = valid address
S0_ADR_I[31:25] = unused
256 M:
S0_ADR_I[23:0] = valid address
S0_ADR_I[31:24] = unused
128 M:
S0_ADR_I[22:0] = valid address
S0_ADR_I[31:23] = unused
S0_DAT_I[31:0],
S1_DAT_I[31:0] Input The data input array used for write data
S0_SEL_I[4:0],
S1_SEL_I[4:0] Input
The select input array indicates where valid data is placed on the DAT_I signal array
during WRITE cycles and where it should be present on the DAT_O signal array dur-
ing READ cycles.
S0_WE_I,
S1_WE_I Input
The write enable Input WE_I indicates whether the current local bus cycle is a
READ or WRITE cycle. The signal is negated during READ cycles and is
asserted during WRITE cycles
S0_CYC_I[2:0],
S1_CYC_I[2:0] Input
The Cycle Input CYC_I, when asserted, indicates that a valid bus cycle is in progress.
The signal is asserted for the duration of all bus cycles.
The CYC_I signal is asserted during the first data transfer and remains asserted until
the last data transfer.
CLK0_I,
CLK1_I Input Wishbone input clocks
RST0_I,
RST1_I Input Wishbone reset
S0_CTI_I,
S1_CTI_I Input Cycle type identifier input. It provides additional information about the current cycle.
S0_BTE_I,
S1_BTE_I Input Burst type extension input. It provides additional information about the current burst.
S0_LOCK_I,
S1_LOCK_I Input Lock input signal. When asserted, it indicates that the current cycle is uninterruptible.
S0_STB_I,
S1_STB_I Input Strobe input. When asserted, it indicates that the core can respond to other Wishbone
signals.
S0_DAT_O[31:0],
S1_DAT_O[31:0] Output The data Output array used for read data
S0_ACK_O,
S1_ACK_O Output The acknowledge output ACK_O, when asserted, indicates the termination of
a normal bus cycle by the slave
S0_ERR_O,
S1_ERR_O Output The error output ERR_O indicates an abnormal cycle termination by the slave.
Functional Description
IPUG92_01.3, February 2014 9 LPDDR SDRAM Controller User’s Guide
Using the Local User Interface
The local user interface of the LPDDR memory controller IP core consists of five independent functional groups:
• Initialization Control
• Command and Address
• Data Write
• Data Read
Each functional group and its associated local interface signals as listed in Table 2-3.
Table 2-3. Local User Interface Functional Groups
Initialization and Training
LPDDR memory devices must be initialized before the memory controller can access them. The memory controller
starts the memory initialization sequence when the init_start signal is asserted by the user interface. Once
asserted, the init_start signal needs to be held high until the initialization process is completed. The output signal
init_done is asserted high for one clock cycle indicating that the core has completed the initialization sequence and
is now ready to access the memory. The init_start signal must be de-asserted as soon as init_done is sampled high
at the rising edge of sclk. If the init_start is left high at the next rising edge of sclk, the memory controller takes it as
another request for initialization and starts the initialization process again. Memory initialization is required immedi-
ately after the system reset or after a deep-power-down exit. Re-initialization after a deep-power-down exit is auto-
matically handled by the core.
Figure 2-2. Timing of Memory Initialization Control
S0_RTY_O,
S1_RTY_O Output The retry output RTY_O indicates that the slave interface is not ready to accept or
send data
S0_INT_O,
S1_INT_O Output Interrupt output. It is for a future use and can be disregarded.
Functional Group Signals
Initialization and Training init_start, init_done, rt_req, rt_done, rt_act, rt_err
Command and Address addr, cmd, cmd_rdy, cmd_valid
Data Write data_rdy, write_data, data_mask
Data Read read_data, read_data_valid
External Auto Refresh ext_auto_ref, ext_auto_ref_ack
Table 2-2. LPDDR SDRAM Memory Controller Top-Level I/O List for Wishbone Interface (Continued)
Port Name I/O Description
clk
init_done
init_start
Functional Description
IPUG92_01.3, February 2014 10 LPDDR SDRAM Controller User’s Guide
LPDDR memory devices do not use DLL, and therefore the controller needs to periodically compensate for pro-
cess, voltage and temperature (PVT) variations. Read training is initially performed immediately following the mem-
ory initialization process. Once the initialization is done, the core automatically performs read re-training during the
normal operations with a user selected training interval. Since a re-training process takes over the LPDDR bus until
it is finished, the core allows re-training only after an auto-refresh burst cycle is finished in order to minimize inter-
ruption of user transactions. The training interval is defined in terms of the number of auto refresh burst cycles. The
user can select every 8th, 64th, 256th, 512th or 1024th auto refresh burst cycle to initiate a read re-training pro-
cess. If a longer period is needed or the training is to be initiated by the user, the Read Re-training User Control
option can be enabled. Once enabled, the rt_req and rt_done signals are added to the user interface. The rt_req
signal can be asserted at any time during a normal operation, but the actual training will start at the end of next
auto refresh burst cycle. The rt_req signal must be de-asserted as soon as rt_done is sampled high at the rising
edge of sclk. Figure 2-3 shows the timing of user read re-training.
Figure 2-3. Timing of User Read Training
Since LPDDR memory devices do not provide a training pattern, the controller must reserve a user address space
to train the bus. The location of the training address space is user configurable through the Address Space for
Training option. The address range of training space is 16 and reserved for all core configurations. If the address
space is set to 23'h003000, for example, the range of the space becomes 23'h003000 to 23'h00300F. The starting
address must be modulo of 16. For example, address 23'h003000 or 23'h003010 is a valid starting address for the
training space. This address space should be avoided in user transactions. If the entire range of addressable mem-
ory space is to be accessed by user application, the user can select the Read Re-training User Control option to
fully take over the control of read training.
Command and Address
Once the memory initialization is done, the core waits for user commands in order to set up and/or access the
memory. User logic needs to provide command and address to the core and drive the control signals appropriately.
The commands and addresses are delivered to the core using the following procedure:
1. The memory controller asserts the signal cmd_rdy for one clock cycle indicating its readiness to receive a com-
mand and address.
2. User logic asserts the signal cmd_valid indicating that the command and address on the bus are valid data.
When the cmd_rdy is high, user logic must de-assert cmd_valid in the next clock cycle if there is no new data, or
keep it high if the bus contains new, valid command and address.
3. When both the cmd_rdy and cmd_valid are high, the core accepts the command and address data on the cmd
and addr buses. User logic must de-assert cmd_valid in the next clock cycle if there is no new valid data on the
cmd and addr buses, or keep it high if the bus contains new, valid command and address as shown in Figure 2-
4.
The assertions of cmd_rdy by the controller and cmd_valid by user logic are independent of each other.
clk
rt_done
rt_req
rt_act
Auto refresh burst ends here Read training starts here
Functional Description
IPUG92_01.3, February 2014 11 LPDDR SDRAM Controller User’s Guide
Figure 2-4. Timing of Command and Address
User Commands
The user initiates a request to the memory controller by loading a specific command code in cmd input along with
other information such as the memory address. The command on the cmd bus must be a valid command. Lattice
LPDDR IP defines a set of valid memory commands as shown in Ta b l e 2 -4 . All other values should not be used.
Table 2-4. Defined User Commands for Generic Interface
Command Mnemonic cmd[3:0]
Read RD 0001
Write WR 0010
Read with Auto Precharge RDA 0011
Write with Auto Precharge WRA 0100
Powerdown Entry PDE 0101
Load Mode Register LMR 0110
Status Register Read SRR 0111
Self Refresh Entry SRE 1000
Self Refresh Exit SRX 1001
Powerdown Exit PDE 1010
Deep Powerdown Entry DPDE 1011
Deep Powerdown Exit DPDX 1100
clk
cmd_valid
cmd_rdy
cmd
addr
C0
A0
C1
A1
C2
A2
Functional Description
IPUG92_01.3, February 2014 12 LPDDR SDRAM Controller User’s Guide
WRITE
The user initiates a memory write operation by asserting cmd_valid along with the WRITE or WRITEA command
and the address. After the WRITE command is accepted, the memory controller core asserts the datain_rdy signal
when it is ready to receive the write data from the user logic to write into the memory. Since the duration from the
time a write command is accepted to the time the datain_rdy signal is asserted is not fixed, the user logic needs to
monitor the datain_rdy signal. Once datain_rdy is asserted, the core expects valid data on the write_data bus one
clock cycle after the datain_rdy signal is asserted. Figure 2-5 shows an example of the local user interface data
write timing. The controller decodes the addr input to extract the current row and current bank addresses and
checks if the current row in the memory device is already opened. If there is no opened row in the current bank an
ACTIVE command is generated by the controller to the memory to open the current row first. Then the memory
controller issues a WRITE command to the memory. If there is already an opened row in the current bank and the
current row address is different from the opened row, a PRECHARGE command is generated by the controller to
close opened row in the bank. This is followed with an ACTIVE command to open the current row. Then the mem-
ory controller issues a WRITE command to the memory. If the current row is already open, only a WRITE com-
mand (without any ACTIVE or PRECHARGE commands) is sent to the memory.
Figure 2-5. One-Clock Write Data Delay
WRITEA
WRITEA is treated in the same way as a WRITE command except that the core issues a Write with Auto Precharge
command to the memory instead of just a WRITE command. This causes the memory to automatically close the
current row after completing the WRITE operation.
READ
When the READ command is accepted, the memory controller core accesses the memory to read the addressed
data and brings the data back to the local user interface. Once the read data is available on the local user interface,
the memory controller core asserts the read_data_valid signal to indicate that the valid read data is on the
read_data bus. The read data timing on the local user interface is shown in Figure 2-6. The READ operation follows
the same row status checking scheme as mentioned in the WRITE operation. Depending on the current row status
the memory controller generates ACTIVE and PRECHARGE commands as required. Refer to the WRITE opera-
tion for more detail.
clk
datain_rdy
write_data
data_mask
clk
datain_rdy
write_data
data_mask
D0 D1 D2 D3 D4 D5
DM0 DM1 DM2 DM3 DM4 DM5
D0
DM0
D2 D3 D4 D5
DM2 DM3 DM4 DM5
BL4
D0 D1
DM0 DM1
D6 D7
DM6 DM7
BL8
61LB2LB
Functional Description
IPUG92_01.3, February 2014 13 LPDDR SDRAM Controller User’s Guide
Figure 2-6. User-Side Read Operation
READA
READA is treated in the same way as a READ command except that the core issues a Read with Auto Precharge
command to the memory instead of a READ command. This makes the memory automatically close the current
row after completing the read operation.
AUTO REFRESH
Since LPDDR memories have at least an 8-deep Auto Refresh command queue as per the JEDEC specification,
the Lattice LPDDR memory controller core supports up to eight Auto Refresh commands in one burst. The core
has an internal Auto Refresh Generator that sends out a set of consecutive Auto Refresh commands to the mem-
ory at once when it reaches the time period of the refresh intervals (tREFI) times the Auto Refresh burst count
selected in the IPexpress GUI. It is recommended that the maximum number be used if the LPDDR interface
throughput is a major concern of the system. If it is set to eight, for example, the core will send a set of eight con-
secutive Auto Refresh commands to the memory once it reaches the time period of the eight refresh intervals (tREFI
x 8). Bursting refresh cycles increases the LPDDR bus throughput because it helps keep core intervention to a
minimum.
SELF REFRESH
The self refresh command comes as a set of two in compliance to JEDEC protocol: self refresh entry and self
refresh exit. The user should always use them as a set, a self refresh exit should always follow a self refresh entry.
To minimize power, the user has the option to turn the memory clock off during self refresh operations. This is a
user-programmable parameter, and when set, the controller will automatically turn off the memory clock. To mini-
mize the power even further, the controller will refresh half or a quarter of the memory if it is set through an MRS
command.
Power Down and Deep Power Down
The power-down commands come as a set of two in compliance to JEDEC protocol: entry and exit. The user
should always use them as a set an exit should always follow an entry. To minimize power, the user has the option
to turn the memory clock off during power-down operations. For deep power entry, the controller will re-initialize the
memory and performs read re-training upon exiting the deep-power-down mode.
EXTERNAL AUTO REFRESH
Alternatively, the user can enable the External Auto Refresh function which will add an input signal ext_auto_ref
and an output signal ext_auto_ref_ack to the core. In this case the internal auto refresh generator is disabled and
the core sends out a burst of refresh commands, as directed by Auto refresh burst count, every time the
ext_auto_ref is asserted. Completion of refresh burst is indicated by the output signal ext_auto_ref_ack. The
ext_auto_ref signal must be de-asserted as soon as ext_auto_ref_ack is sampled high at the rising edge of sclk.
Figure 2-7 shows the timing of external user auto refresh. If there is an application where explicit memory refresh is
not necessary, the user still needs to enable External Auto Refresh and keep the minimum refresh effort so that the
read re-training can be initiated from the auto refresh bursts.
read_data_valid
read_data
Burst Length = 2 Burst Length = 4 Burst Length = 8
Burst Length = 16
read_data_valid
read_data
D0 D0 D1 D0 D1 D2 D3
D0 D1 D2 D3 D4 D5 D6 D7
Functional Description
IPUG92_01.3, February 2014 14 LPDDR SDRAM Controller User’s Guide
Figure 2-7. Timing of External User Auto Refresh
User Commands for Wishbone Interface
The LPDDR controller has a GUI selectable interface compliant to two port WISHBONE bus. Port_0 is used for
read/writes and port_1 for programming the mode register and executing special commands like power down, deep
power down or self refresh. Once the WISHBONE option is enabled, only the BL2 (Burst Length=2) mode is sup-
ported. When the port_1 WISHBONE bus is used to program the mode register, BL2 should be selected for Burst
Length.
The memory command mapping of the port_1 wishbone bus are described in Table 2-5.
Table 2-5. Memory Command Mapping of the port_1 Wishbone Bus
S1_ADR_I S1_DAT_I Command Description
32‘h1 Valid data =[B6, … B0] MRS
Bits [B2,B1,B0] = Burst length
Bits [B3] = Burst type
Bits [B6,B5,B4] = CAS latency
---------------------------------
Bits [31, … B7] = Don’t Care
32‘h2 Valid data =[B7, … B0] EMRS
Bits [B2,B1,B0] = PASR
Bits [B4,B3] = TCSR
Bits [B7,B6,B5] = Drive Strength
---------------------------------
Bits [31, … B8] = Don’t Care
32’h4 Don’t Care PDE Power Down Entry
32’h8 Don’t Care PDX Power Down Exit
32’h10 Don’t Care DPDE Deep Power Down Entry
32’h20 Don’t Care DPDX Deep Power Down Exit
32’h40 Don’t Care SRE Self Refresh Entry
32’h80 Don’t Care SRX Self Refresh Exit
32’h100 Don’t Care SRR Status Register Read
clk
ext_auto_ref_ack
ext_auto_ref
Functional Description
IPUG92_01.3, February 2014 15 LPDDR SDRAM Controller User’s Guide
Local-to-Memory Address Mapping
Mapping local addresses to memory addresses is an important part of a system design when a memory controller
function is implemented. Users must know how the local address lines from the memory controller connect to a
memory device's address lines because proper local-to-memory address mapping is crucial to meet the system
requirements in applications such as video frame buffering. Even for other applications, careful address mapping is
generally necessary to optimize system performance. On the memory side, the address (A) and bank address (BA)
inputs are used for addressing a memory device. Users can obtain this information from the device data sheet.
Figure 2-8 shows the local-to-memory address mapping of the Lattice LPDDR memory controller core.
Figure 2-8. Local-to-Memory Address Mapping for Memory Access
Mode Register Programming
The LPDDR SDRAM memory devices are programmed using the mode registers MRS and EMRS. The bank
address bus (em_ddr_ba) is used to choose one of the Mode registers, while the programming data is delivered
through the address bus (em_ddr_addr). The memory data bus cannot be used for mode register programming.
The Lattice LPDDR memory controller core uses the local address bus, addr, to program these registers. The core
accepts a user command, LMR, to initiate the programming of mode registers. When LMR is applied on the cmd
bus, the user logic must provide the information for the targeted mode register and the programming data on the
addr bus. When the target mode register is programmed, the memory controller core is also configured to support
the new memory setting. Table 2-6 shows how the local address lines are allocated for selecting mode registers.
The addr[7:0] lines are used to provide the contents for the selected mode register.
Table 2-6. Mode Register Selection Using Bank Address Bits
Mode Register (addr[9:8])
MRS 00
EMRS 10
BA Address Column Address
(COL_WIDTH)
Row Address
(ROW_WIDTH)
addr[ADDR_WIDTH-1:0]
0
COL_WIDTH + 1 COL_WIDTH - 1ADDR_WIDTH - 1
IPUG92_01.3, February 2014 16 LPDDR SDRAM Controller User’s Guide
The IPexpress™ tool is used to create IP and architectural modules in the Diamond design software. Table 3-1 pro-
vides a list of user-configurable parameters for this IP core. The parameter settings are specified using the LPDDR
SDRAM Controller IP core Configuration GUI in IPexpress.
Table 3-1. LPDDR Core Configuration Parameters
Parameters in GUI Range/Options Default
Select Memory
MT46H8M16LF
MICRON MT46H8M16LF
MT46H16M16LF
MT46H32M16LF
MT46H64M16LF
MT46H128M16LF
CUSTOM
Clock 10~133 133MHz (Wishbone off, -6 SP grade)
100 MHz (All other cases)
Memory Data Bus Size 8, 16 16
Clock Width 1 1
Wishbone Bus Disable, One Port, Two Ports Disable
Row Size 12-14 12
Column Size 9-11 9
Bank Size 2 2
Chip Select Width 1 1
Auto refresh burst count 2-8 8
External Auto Refresh (User Refresh Control) Selected/ Unselected Unselected
Read Re-training Auto Re-training User Control Auto Re-training
Re-training Period (N) 8, 64, 256, 512, 1024 1024
Address Space for Training ‘h0 to {`ADDR_WIDTH{1’b1}} -4’hf 23`h000000
Read Data Auto Alignment Selected/ Unselected Unselected
Partial Array Self Refresh Full, Half, Quarter Full
Memory Clock OFF Selected/ Unselected Unselected
Burst Length 2, 4, 8, 16 with Generic,
2 with Wishbone
8 with Generic,
2 with Wishbone
Burst Type Sequential, Interleave Sequential
CAS Latency 3 3
Active to Read/Write (TRCD) 3~7 3
Active to Precharge (TRAS) 6~15 6
AutoRefresh Cmd Period (TRFC) 15~31 15
Load_Mode Cmd Period (TMRD) 2~3 2
Precharge Cmd Period (TRP) 3 3
Active to Active Cmd (TRC) 9~15 10
Avr. Refresh Cmd Interval (TREFI) Max = Int(7.8xClock) Int(7.8xClock)
Write to Read (TWTR) 1~3 1
Power Down to Next Cmd (TXP) 1~7 2
Min CKE High/Low (TCKE) 4~7 4
Exit Self Ref to Next Cmd (TXSR) 11~63 27
SRR to Read (TSRR) 2~3 2
SRR to Next Cmd (TSRC) 4~7 4
Write Recovery (TWR) 2~3 2
Chapter 3:
Parameter Settings
Parameter Settings
IPUG92_01.3, February 2014 17 LPDDR SDRAM Controller User’s Guide
Mode Tab
The Memory Type Selection field is not a user option but is selected by IPexpress when an LPDDR SDRAM Con-
troller core is selected from the IPexpress IP core list. Figure 3-1 shows the contents of the Mode tab.
Figure 3-1. Mode Options in the IPexpress Tool
Type Tab
The Type tab allows the user to select the LPDDR controller configuration for the target memory device and the
core functional features. These parameters are considered as static parameters since the values for these param-
eters can only be set in the GUI. The LPDDR controller must be regenerated to change the value of any of these
parameters.
Figure 3-2 shows the contents of the Type tab.
Figure 3-2. Type Options in the IPexpress Tool
Select Memory
The LPDDR 128Mb x16 from Micron Technology® is provided as the default LPDDR memory. The timing parame-
ters of this memory are listed in the Memory Device Timing tab as default values.
Clock
This parameter specifies the frequency of the memory clock to the on-board memory. The supported frequency
range is from 10MHz up to 100MHz or 133MHz depending on the interface mode and the device speed grade.
Parameter Settings
IPUG92_01.3, February 2014 18 LPDDR SDRAM Controller User’s Guide
Memory Data Bus Size
The MachXO2 device family provides a 8- or 16-bit I/O interface to the LPDDR memory.
Clock Width
The controller provides one differential clock for the LPDDR memory.
Wishbone Bus
The controller supports both the Lattice generic user interface and Wishbone bus. One Port or Two Ports option is
selected to use the Wishbone bus.
Setting Tab
Figure 3-3 shows the contents of the Setting tab.
Figure 3-3. Setting Options in the IPexpress Tool
Parameter Settings
IPUG92_01.3, February 2014 19 LPDDR SDRAM Controller User’s Guide
Row Size
This option indicates the Row Address size used in the selected memory configuration.
Column Size
This option indicates the Column Address size used in the selected memory configuration.
Auto Refresh Burst Count
This option indicates the number of Auto Refresh commands that the memory controller core is set to send in a sin-
gle burst.
External Auto Refresh
This option, if selected, allows the user logic to generate an auto refresh request to the controller. If this option is
not selected, the controller automatically generates refresh commands to the memory at the interval defined by the
memory refresh timing requirement (TREFI) and Auto Refresh Burst Count.
Read Re-training
This option selects whether the periodic read re-training is governed by the controller or the user. If the User Con-
trol option is selected, two additional ports, rt_req and rt_done, are added to the user interface. If the Auto Re-train-
ing is selected, the core automatically initiates read re-training requests following the user selected training interval,
Re-training Period.
Re-training Period
This option defines a training interval in terms of the number of auto refresh burst cycles. This option is available
when the Auto Re-training option is selected with the 8th, 64th, 256th, 512th or 1024th auto refresh burst cycles to
choose from. The controller will initiate read re-training once every selected number of auto refresh burst cycles.
Address Space for Training
This option assigns the location of training address space to the user address map. The size of training address
space is determined by the selected burst length, and only the start address needs to be entered. BL2, BL4, BL8 or
BL16 use 2, 4, 8 or 16 address locations respectively.
Read Data Auto Alignment
This option selects whether the controller automatically deskews and aligns the read data and read data valid sig-
nals or not. Once enabled, the read_data_valid signal becomes a single bit output fully aligned with the read data
also deskewed between two DQS groups. This option should be enabled when dynamic skew is observed on the
read data and two-bit read_data_valid between two DQS groups. It is generally expected that an implemented
LPDDR controller core does not show a skew in most cases. If there is skew observed on the read data, however,
assertion timing differences by one clock between two read_data_valid bits will also be dynamically observed. This
dynamic skew can occur when a specific length of round trip delay of a system makes the incoming DQS edges
aligned with the system clock, and the jitter on the LPDDR bus dynamically changes the clock relationships. When
this dynamic skew is observed, the core needs to be regenerated with the Read Data Auto Alignment option
enabled. The auto alignment mode removes the dynamic skew and aligns the read data with the read data valid
signal. Since the auto alignment mode adds about three clocks of additional latency with increased lut counts, it is
recommended that this option be enabled only when dynamic skew is observed. When disabled, either of two
read_data_valid bits can be used to validate the read data because they are identical when there is no skew
observed.
Partial Array Self Refresh
For power saving purposes, the controller has the capability to refresh a quarter, a half or full memory, if the user is
accessing only a quarter, a half or full memory, during self refresh operations.
Parameter Settings
IPUG92_01.3, February 2014 20 LPDDR SDRAM Controller User’s Guide
Memory Clock
This is an on/off option and if enabled, the controller will turn the memory clock off during self refresh, power down
and deep power down operations.
Burst Length
This option sets the burst length value in the mode register during initialization. When Wishbone is selected, only
the BL2 mode is supported.
CAS Latency
This option sets the CAS latency value in the mode register during initialization.
Burst Type
This option sets the burst type value in the mode register during initialization.
Parameter Settings
IPUG92_01.3, February 2014 21 LPDDR SDRAM Controller User’s Guide
Memory Device Timing Tab
Figure 3-4 shows the contents of the Memory Device Timing tab.
Figure 3-4. Memory Device Timing Options in the IPexpress Tool
Manually Adjust
Checking this box allows users to manually set (via increment/decrement) any of the memory timing parameters. If
the user needs to change any of the default values, the Manually Adjust checkbox must be checked. This selection
will enable the user to increment/decrement the memory timing parameters.
tCLK – Memory Clock
This is a notation signifying that the memory timing parameters shown in this tab are specified in terms of tCLK
LPDDR memory clock cycles.
Parameter Settings
IPUG92_01.3, February 2014 22 LPDDR SDRAM Controller User’s Guide
Synthesis and Simulation Tab
The Synthesis and Simulation tab enables the user to select the simulation and synthesis tools to be used for gen-
erating a design. Figure 3-5 shows the contents of the Design Tools Options and Info tab.
Figure 3-5. Synthesis and Simulation Options in the IPexpress Tool
The tab supports the following parameters:
Support Synplify
If selected, IPexpress generates evaluation scripts and other associated files required to synthesize the top-level
design using the Synopsys Synplify synthesis tool.
Support LSE
If selected, IPexpress generates evaluation scripts and other associated files required to synthesize the top-level
design using LSE.
Support ModelSim
If selected, IPexpress generates evaluation script and other associated files required to synthesize the top-level
design using the Mentor Graphics ModelSim simulator.
Support Active HDL
If selected, IPexpress generates evaluation script and other associated files required to synthesize the top-level
design using the Aldec® Active-HDL® simulator.
Core Synthesis with Lattice LSE
If selected, IPexpress generates the encrypted netlist for the core using LSE.
Parameter Settings
IPUG92_01.3, February 2014 23 LPDDR SDRAM Controller User’s Guide
Info Tab
This tab provides information about the pinout resources used. Figure 3-6 shows the contents of the Info tab.
Figure 3-6. Info Tab in the IPexpress Tool
Memory I/F Pins
This section displays information for the LPDDR memory interface pins.
Number of BiDi Pins
This is a notification of the number of bi-directional pins used in the memory side interface for the selected configu-
ration. Bi-directional pins are used for Data (DQ) and Data Strobe (DQS) signals only.
Number of Output Pins
This is a notification of the number of output-only pins used in the memory side interface for the selected configura-
tion. Output-only pins are used for LPDDR Address, Command and Control signals.
User I/F Pins
This section displays the information for the user interface pins.
Number of Input Pins
This is a notification of the number of input pins used in the user interface for the selected configuration.
Number of Output Pins
This is a notification of the number of output pins used in the user interface for the selected configuration.
IPUG92_01.3, February 2014 24 LPDDR SDRAM Controller User’s Guide
This chapter provides information on how to generate the LPDDR SDRAM IP core using the Diamond IPexpress
tool, and how to include the core in a top-level design.
The LPDDR SDRAM IP core can be used in the MachXO2 device family. For example information and known
issues on this IP core see the Lattice LPDDR IP ReadMe document. This file is available once the core is installed
in Diamond. The document provides information on creating an evaluation version of the core for use in simulation.
Users may download and generate the LPDDR SDRAM IP core and fully evaluate the core through functional sim-
ulation and implementation (synthesis, map, place and route) without an IP license. The LPDDR SDRAM IP core
also supports Lattice’s IP hardware evaluation capability, which makes it possible to create versions of the IP core
that operate in hardware for a limited time (approximately four hours) without requiring an IP license. See “Hard-
ware Evaluation” on page 30 for further details. However, a license is required to enable timing simulation, to open
the design in the Diamond EPIC tool, and to generate bitstreams that do not include the hardware evaluation time-
out limitation.
Getting Started
The LPDDR SDRAM IP core is available for download from the Lattice’s IP Server using the IPexpress tool. The IP
files are automatically installed using ispUPDATE technology in any customer-specified directory. After the IP core
has been installed, the IP core will be available in the IPexpress GUI dialog box shown in Figure 4-1.
The IPexpress tool GUI dialog box for the LPDDR SDRAM IP core is shown in Figure 4-1. To generate a specific IP
core configuration the user specifies:
•Project Path – Path to the directory where the generated IP files will be loaded.
•File Name – “username” designation given to the generated IP core and corresponding folders and files.
• Module Output – Verilog or VHDL.
•Device Family – Device family to which IP is to be targeted. Only families that support the particular IP core are
listed.
•Part Name – Specific targeted part within the selected device family.
Figure 4-1. IPexpress Dialog Box
Chapter 4:
IP Core Generation
IP Core Generation
IPUG92_01.3, February 2014 25 LPDDR SDRAM Controller User’s Guide
Note that if the IPexpress tool is called from within an existing project, Project Path, Design Entry, Device Family
and Part Name default to the specified project parameters. Refer to the IPexpress tool online help for further infor-
mation.
To create a custom configuration, the user clicks the Customize button in the IPexpress tool dialog box to display
the LPDDR SDRAM IP core Configuration GUI, as shown in Figure 4-2. From this dialog box, the user can select
the IP parameter options specific to their application
Figure 4-2. LPDDR SDRAM IP Configuration GUI
IP Core Generation
IPUG92_01.3, February 2014 26 LPDDR SDRAM Controller User’s Guide
IPexpress-Created Files and Top Level Directory Structure
When the user clicks the Generate button in the IP Configuration dialog box, the IP core and supporting files are
generated in the specified Project Path directory. The directory structure of the generated files is shown in Figure 4-
3.
Figure 4-3. MachXO2 LPDDR Core Directory Structure
LPDDR SDRAM Controller IP Core File Structure
Table 4-1 provides a list of key files and directories created by the IPexpress tool and how they are used. The IPex-
press tool creates several files that are used throughout the design cycle. The names of most of the created files
are customized to the user’s module name specified in the IPexpress tool.
Table 4-1. File List
File Description
<username>.v This file provides the LPDDR SDRAM core for simulation.
<username>_beh.v This file provides a behavioral simulation model for the LPDDR SDRAM core.
<username>_bb.v This file provides the synthesis black box for the user’s synthesis.
<username>.ngo The ngo files provide the synthesized IP core.
<username>.lpc This file contains the IPexpress tool options used to recreate or modify the core in the IPex-
press tool.
<username>.ipx
The IPX file holds references to all of the elements of an IP or Module after it is generated from
the IPexpress tool. The file is used to bring in the appropriate files during the design implemen-
tation and analysis. It is also used to re-load parameter settings into the IP/Module generation
GUI when an IP/Module is being re-generated.
IP Core Generation
IPUG92_01.3, February 2014 27 LPDDR SDRAM Controller User’s Guide
The LPDDR SDRAM Controller IP core consists of the following four major functional blocks:
• Top-level wrapper (RTL)
• Obfuscated memory controller core and I/O modules for simulation and encrypted netlist memory controller core
for synthesis
• Clock generator (RTL for simulation and Verilog flow synthesis or netlist for VHDL flow synthesis) All of these
blocks are required to implement the IP core on the target device. Figure 4-4 depicts the interconnection among
those blocks.
Figure 4-4. File Structure of LPDDR SDRAM Controller IP Core
Top-level Wrapper
The obfuscated core, obfuscated I/O modules, and the clock generator block are instantiated in the top-level wrap-
per. When a system design is made with the LPDDR SDRAM Controller IP Core, this wrapper must be instantiated.
The wrapper is fully parameterized by the generated parameter file.
Obfuscated Module for the Core and I/O Modules
Obfuscated RTL files are used for simulation. The obfuscated core contains the memory controller function and I/O
modules that interface with the user logic on one side and with the LPDDR memory on the other side. An equiva-
lent netlist of the core is provided for synthesis.
<username>_top.[v,vhd]
This file provides a module which instantiates the LPDDR SDRAM core. This file can be easily
modified for the user's instance of the LPDDR SDRAM core. This file is located in the
lpddr_eval/<username>/src directory.
<username>_generate.tcl This file is created when GUI “Generate” button is pushed. This file may be run from command
line.
<username>_generate.log This is the IPexpress scripts log file.
<username>_gen.log This is the IPexpress IP generation log file
<username>.v This file provides the LPDDR SDRAM core for simulation.
Table 4-1. File List (Continued)
File Description
Parameter File
Core
(Obfuscated
Source File)
LPDDR MemoryLocal User Logic
Top-Level Wrapper (RTL)
I/O Modules
(Obfuscated
Source File)
IP Core Generation
IPUG92_01.3, February 2014 28 LPDDR SDRAM Controller User’s Guide
Simulation Files for IP Core Evaluation
Once a LPDDR SDRAM Controller IP core is generated, it contains a complete set of test bench files to simulate a
few example core activities for evaluation. The simulation environment for the LPDDR memory controller IP is
shown in Figure 4-5. This structure can be reused by system designers to accelerate their system validation.
Figure 4-5. Simulation Structure for LPDDR Memory Controller Core Evaluation
Test Bench Top
The test bench top includes the core under test, memory model, stimulus generator and monitor blocks. It is
parameterized by the core parameter file.
Obfuscated Core and I/O Simulation Models
The obfuscated simulation model for the core and I/O modules are instantiated in the top-level wrapper. This obfus-
cated simulation model must be included in the simulation.
Command Generator
The command generator generates stimuli for the core. The core initialization and command generation activities
are predefined in the provided test case module. It is possible to customize the test case module to see the desired
activities of the core.
Monitor
The monitor block monitors both the local user interface and LPDDR interface activities and generates a warning or
an error if any violation is detected. It also validates the core data transfer activities by comparing the read data
with the written data.
Memory Model
The LPDDR SDRAM Controller test bench uses a memory simulation model provided by one of the most popular
memory vendors. If a different memory model is required, it can be used by simply replacing the instantiation of the
model from the memory configuration modules located in the same folder.
Parameter File
Testbench Top
Monitor
Command
Generator
Memory
Model
Parameters
Obfuscated
Sim Model
Top-level
Wrapper
IP Core Generation
IPUG92_01.3, February 2014 29 LPDDR SDRAM Controller User’s Guide
Memory Model Parameter
This memory parameter file comes with the memory simulation model. It contains the parameters that the memory
simulation model needs. It is not necessary for users to change any of these parameters.
Evaluation Script File
ModelSim and Aldec Active-HDL simulation macro script files are included for instant evaluation of the IP core. All
required files for simulation are included in the macro script. This simulation script can be used as a starting point
of a user simulation project.
Instantiating the Core
The generated LPDDR SDRAM IP core package includes black-box (<username>_bb.v) and instance (<user-
name>_inst.v) templates that can be used to instantiate the core in a top-level design. An example RTL top-level
reference source file that can be used as an instantiation template for the IP core is provided in
\<project_dir>\lpddr_eval\<username>\src\rtl\top. Users may also use this top-level reference as
the starting template for the top-level for their complete design.
Running Functional Simulation
Simulation support for the LPDDR SDRAM IP core is provided for Aldec and ModelSim simulators. The LPDDR
SDRAM core simulation model is generated from the IPexpress tool with the name <username>.v. This file calls
<username>_beh.v which contains the obfuscated simulation model. An obfuscated simulation model is Lattice’s
unique IP protection technique which scrambles the Verilog HDL while maintaining logical equivalence. VHDL
users will use the same Verilog model for simulation.
The ModelSim environment is located in \<project_dir>\lpddr_eval\<username>\sim\modelsim. Users
can run the ModelSim simulation by performing the following steps:
1. Open ModelSim.
2. Under the File tab, select Change Directory and choose folder
\<project_dir>\lpddr_eval\<username>\sim\modelsim.
3. Under the Tools tab, select Tcl > Execute Macro and execute the ModelSim "do" script shown.
The Aldec Active-HDL environment is located in \<project_dir>\lpddr_eval\<username>\sim\aldec.
Users can run the Aldec evaluation simulation by performing the following steps:
1. Open Active-HDL.
2. Under the Tools tab, select Execute Macro.
3. Browse to the directory \<project_dir>\lpddr_eval\<username>\sim\aldec and execute the Active-
HDL "do" script shown.
IP Core Generation
IPUG92_01.3, February 2014 30 LPDDR SDRAM Controller User’s Guide
Synthesizing and Implementing the Core in a Top-Level Design
The LPDDR SDRAM IP core itself is synthesized and provided in NGO format when the core is generated through
the IPexpress tool. You can combine the core in your own top-level design by instantiating the core in your top level
file as described in “Instantiating the Core” on page 29 and then synthesizing the entire design with LSE or Synplify
RTL Synthesis.
Push-button implementation of this top-level design with LSE or Synplify RTL Synthesis is supported via the project
files <username>_eval.ldf located in the \<project_dir>\lpddr_eval\<username>\impl\LSE (or syn-
plify) directory.
To use this project file:
1. Choose File > Open > Project.
2. Browse to \<project_dir>\lpddr_eval\<username>\impl\LSE (or synplify) in the Open Project
dialog box.
3. Select and open <username>_eval.ldf. At this point, all of the files needed to support top-level synthesis and
implementation will be imported to the project.
4. Select the Process tab in the left-hand GUI window.
5. Implement the complete design via the standard Diamond GUI flow.
Hardware Evaluation
The LPDDR SDRAM IP core supports Lattice’s IP hardware evaluation capability, which makes it possible to create
versions of the IP core that operate in hardware for a limited period of time (approximately four hours) without
requiring the purchase of an IP license. It may also be used to evaluate the core in hardware in user-defined
designs.
Enabling Hardware Evaluation
Choose Project > Active Strategy > Translate Design Settings. The hardware evaluation capability may be
enabled/disabled in the Strategy dialog box. It is enabled by default.
Updating/Regenerating the IP Core
By regenerating an IP core with the IPexpress tool, you can modify any of its settings including device type, design
entry method, and any of the options specific to the IP core. Regenerating can be done to modify an existing IP
core or to create a new but similar one.
Regenerating an IP Core
To regenerate an IP core:
1. In IPexpress, click the Regenerate button.
2. In the Regenerate view of IPexpress, choose the IPX source file of the module or IP you wish to regenerate.
3. IPexpress shows the current settings for the module or IP in the Source box. Make your new settings in the Tar-
get box.
4. If you want to generate a new set of files in a new location, set the new location in the IPX Target File box. The
base of the file name will be the base of all the new file names. The IPX Target File must end with an .ipx exten-
sion.
5. Click Regenerate. The module’s dialog box opens showing the current option settings.
IP Core Generation
IPUG92_01.3, February 2014 31 LPDDR SDRAM Controller User’s Guide
6. In the dialog box, choose the desired options. To get information about the options, click Help. Also, check the
About tab in IPexpress for links to technical notes and user guides. IP may come with additional information. As
the options change, the schematic diagram of the module changes to show the I/O and the device resources
the module will need.
7. To import the module into your project, if it’s not already there, select Import IPX to Diamond Project (not
available in stand-alone mode).
8. Click Generate.
9. Check the Generate Log tab to check for warnings and error messages.
10.Click Close.
The IPexpress package file (.ipx) supported by Diamond holds references to all of the elements of the generated IP
core required to support simulation, synthesis and implementation. The IP core may be included in a user's design
by importing the .ipx file to the associated Diamond project. To change the option settings of a module or IP that is
already in a design project, double-click the module’s .ipx file in the File List view. This opens IPexpress and the
module’s dialog box showing the current option settings. Then go to step 6 above.
IPUG92_01.3, February 2014 32 LPDDR SDRAM Controller User’s Guide
This chapter provides application support information for the MachXO2 LPDDR SDRAM Controller IP core.
Core Implementation
This section describes the major factors that are important for a successful LPDDR memory controller implementa-
tion.
Understanding Preferences
The following preferences are found in the provided logical preference files (.lpf):
•FREQUENCY – The LPDDR SDRAM Controller IP core is normally over-constrained for obtaining optimal fMAX
results.
•IOBUF – The IOBUF preference assigns the required I/O types to the LPDDR I/O pads.
•LOCATE – For all MachXO2 devices the memory data and data strobe pins are located at the right side of the
device. For this reason these I/Os are grouped and locked to Bank 1.
Chapter 5:
Application Support
IPUG92_01.3, February 2014 33 LPDDR SDRAM Controller User’s Guide
The functionality of the MachXO2 LPDDR SDRAM Controller IP core has been verified via simulation with LPDDR
simulation models from Micron Technology, including:
• Simulation environment verifying proper LPDDR functionality using Lattice’s proprietary verification environment.
Chapter 6:
Core Verification
IPUG92_01.3, February 2014 34 LPDDR SDRAM Controller User’s Guide
This chapter contains information about Lattice Technical Support, additional references, and document revision
history.
Lattice Technical Support
There are a number of ways to receive technical support.
E-mail Support
techsupport@latticesemi.com
Local Support
Contact your nearest Lattice Sales Office.
Internet
www.latticesemi.com
References
•DS1035, MachXO2 Family Data Sheet
JEDEC Web Site
The JEDEC website contains specifications and documents referred to in this user's guide. The JEDEC URL is:
www.jedec.org.
Revision History
November 2010 Initial release.
December 2011 Updated Quick Facts table.
Updated LPDDR Core Configuration Parameters table.
Appendix A – Updated Performance and Resource Utilization table for
MachXO2.
Removed references to ispLEVER® design software.
October 2012 Updated document with new corporate logo.
LPDDR SDRAM Memory Controller Top-Level I/O List for Generic Interface –
Clarified description for the read_data_valid[1:0] port.
February 2014 Added description for the read data auto deskew/alignment function.
Updated signal descriptions table:
- Added ports for user read re-training and user refresh control.
- Signal name changes (datain, dmsel -> write_data, data_mask).
Updated diagrams for new and revised functions.
Added LSE synthesis flow.
Updated descriptions for the core generation GUI.
Updated Lattice Technical Support information.
Date
Document
Version
IP Core
Version Change Summary
01.0 1.0
01.1 1.0
01.2 1.0
01.3 2.0
Chapter 7:
Support Resources
IPUG92_01.3, February 2014 35 LPDDR SDRAM Controller User’s Guide
This appendix gives resource utilization information for Lattice FPGAs using the LPDDR SDRAM Controller IP
core. IPexpress is the Lattice IP configuration utility, and is included as a standard feature of the Diamond design
software. Details regarding the use of IPexpress can be found in the IPexpress and Diamond help systems. For
more information on the Diamond design software, visit the Lattice web site at: www.latticesemi.com.
MachXO2 Devices
Tabl e A -1 lists performance and resource utilization data for four LPDDR SDRAM configurations.
Table A-1. Performance and Resource Utilization1
Ordering Part Number
The Ordering Part Number (OPN) for the LPDDR SDRAM Controller IP on MachXO2 devices is:
LPDDRCT-WB-M2-U
IP Core Parameter Settings Slices LUTs Registers I/O
fMAX
(MHz)2
LPDDR 16-bit, Generic
Default parameters
883 1678 880 147 133
LPDDR 8-bit, Generic 859 1622 849 102 133
LPDDR 16-bit, Wishbone 1 Port 787 1524 933 143 100
LPDDR 8-bit, Wishbone 1 Port 722 1384 835 99 100
1. Performance and utilization data are generated using a LCMXO2-7000HE-6FG484C in Lattice Diamond 3.1 design software. Performance
may vary when using this IP core in a different density, speed or grade within the MachXO2 family.
2. The LPDDR IP core can operate up to 133 MHz (266Mbps LPDDR) in the fastest speed-grade device (-6) when the Lattice generic inter-
face is used.
Appendix A:
Resource Utilization
