PRELIMINARY W541C250
4-BIT MICROCONTROLLER
Publication Release Date: Feb 2002
- 1 - Revision A2
GENERAL DESCRIPTION
The W541C250 is fully compatible with W741C250 in terms of pin assignment and IC function.. It is a
high-performance 4-bit microcontroller (µC) that provides an LCD driver. The device contains a 4-bit
ALU, two 8-bit timers, a divider, a 24 × 4 LCD driver, and five 4-bit I/O ports (including 1 output port for
LED driving). There are also five interrupt sources and 8-level subroutine nesting for interrupt
applications. The W541C250 operates on low voltage and very low current and has two power
reduction modes, hold mode and stop mode, which help to minimize power dissipation.
The W541C250 is suitable for remote controllers, watches and clocks, multiple I/O products, keyboard
controllers, speech synthesis LSI controllers, and other products.
FEATURES
• Operating voltage: 2.4 ~ 5.5V (LCD drive voltage: 3.0V, or 4.5V)
• Single system clock
− Oscillation frequency up to 4 MHz , Crystal or RC oscillator is selected by mask code option ,
− High-frequency (400 KHz to 4 MHz) or low-frequency (32.768 KHz) oscillation is delected by mask
code option
• Memory
− 2048 × 16 bit program ROM (including 2K × 4 bit look-up table)
− 128 × 4 bit data RAM (including 16 working registers)
− 24 × 4 LCD data RAM
• 21 input/output pins
− Ports for input only: 2 ports/8 pins
− Input/output ports: 2 ports/8 pins
− Port for output only: 1 port /4 pins (high sink current to drive LEDs)
− MFP output pin: 1 pin (MFP)
• Power-down mode
- Hold function: no operation (except for oscillator)
- Stop function: no operation (including main clock)
• Five types of interrupts
− Three internal interrupts (Divider 0, Timer 0, Timer 1)
− Two external interrupt (Port RC and INTpin)
• LCD driver output
− 24 segment × 4 common
− Static, 1/2 duty (1/2 bias), 1/3 duty (1/2 or 1/3 bias), 1/4 duty (1/3 bias) driving mode can be
selected
− LCD driver output pins can be used as DC output ports; selectable by code option
W541C250
Publication Release Date: Feb 2002
- 2 - Revision A2
• MFP output pin
− Output is software selectable as modulating or nonmodulating frequency
− Works as frequency output specified by Timer 1
• Built-in 14-bit clock frequency divider circuit
• Two built-in 8-bit programmable countdown timers
− Timer 0: one of two internal clock frequencies (FOSC/4 or FOSC/1024) can be selected
− Timer 1: includes an auto-reload function; and one of two internal clock frequencies (FOSC or
FOSC/64) can be selected or falling edge of pin RC.0 can be selected (output through MFP pin)
• Built-in 18/14-bit watchdog timer selectable for system reset
• Powerful instruction set: 115 instructions
• 8-level subroutine (include interrupt) nesting
• Up to 1 µS instruction cycle (with 4 MHz operating frequency)
• Packaged in 64-pin QFP
BLOCK DIAGRAM
LCD DRIVER
PC
STACK
(8 Levels)
RAM
(128*4)
ALU
Timer 0
(8 Bit)
Timing Generator
PORT RA
PORT RB
PORT RD
PORT RC
Modulation
Frequency
Pulse
SEG0 to SEG23 COM0 to COM3
RA0 to 3
RB0 to 3
RD0 to 3
RC0 to 3
RE0 to 3
MFP
XIN XOUT
VDD
VSS
VDD1 to 3 DH1 to 2
ROM
(2048*16)
(look_up table
2K*4)
Timer 1
(8 Bit)
ACC
RES
INT
Divider 0
(14 Bit)
Watchdog Timer
(4 Bit)
HCF
PEFHEFIEF
Central Control
Unit
EVF SEF
PSR0 PR MR1
..
MUX
SEL
+1(+2)
PORT RE
.
W541C250
Publication Release Date: Feb 2002
- 3 - Revision A2
PIN CONFIGURATION
51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33
12345678910 11 12 13 14 15 16 17 18 19
20
21
22
23
24
25
26
27
28
29
30
31
32
52
53
54
55
56
57
58
59
60
61
62
63
64RD1
RD0
RC3
RC2
RC1
RC0
RB3
RB1
M
F
P
/
I
N
T
/
R
E
S
X
I
N
O
U
T
V
DNN
DCC
D
H
1
D
H
2
V
D
D
SEG18
SEG17
SEG16
SEG15
SEG14
SEG13
SEG12
SEG11
SEG10
R
E
2
R
E
3
V
S
S
N
CN
CC
O
M
C
O
M
C
O
M
C
O
M
S
E
G
S
E
G
S
E
G
S
E
G
S
E
G
S
E
G
3210012345
RDDEE
RRR
2301
SSSEEE
GGE
G
2109
G
SEG9
SEG8
SEG7
SEG6
RB0
RA3
RA2
RA1
RB2
S
2221
S
E
G
3
2
3
V
D
D
2
V
D
D
X
R
A
01
W541C250
Publication Release Date: Feb 2002
- 4 - Revision A2
PAD DESCRIPTION
SYMBOL I/O FUNCTION
XIN I Input pin for oscillator.
Connected to crystal or resistor to generate system clock by code option.
External 15~20pF capacitor uses to get accurate freq in crystal mode.
XOUT O Output pin for oscillator.
Connected to crystal or resistor to generate system clock by code option.
20PF capacitor is built in internal for crystal mode.
RA0−RA3 I/O Input/Output port.
Input/output mode specified by port mode 1 register (PM1).
RB0−RB3 I/O Input/Output port.
Input/output mode specified by port mode 2 register (PM2).
RC0−RC3 I 4-bit port for input only.
Each pin has an independent interrupt capability.
RD0−RD3 I 4-bit port for input only.
RE0−RE3 O Output port only.
This port provides high sink current to drive LEDs.
MFP
O Output pin only.
This pin can output modulating or nonmodulating frequency, or Timer 1
clock output specified by mode register 1 (MR1).
INT I External interrupt pin with pull-high resistor.
RES I System reset pin with pull-high resistor.
SEG0−SEG23 O LCD segment output pins.
Can also be used as DC output ports specified by code option.
COM0−COM3 O LCD common signal output pins.
Static
COM0
COM1
COM2
COM3
Used
Not Used
1/2 Duty
Not Used
Not Used
Not Used
Not Used
1/3 Duty
Not Used
1/4 Duty
Used
Used
Used
Used
Used
Used
Used
Used
Used
The LCD alternating frequency can be selected by code option.
DH1, DH2 I Connection terminals for voltage doubler (halver) capacitor.
VDD1, VDD2
VDD3
I Positive (+) supply voltage terminal.
Refer to Functional Description.
VDD I Positive power supply (+).
VSS I Negative power supply (-).
W541C250
Publication Release Date: Feb 2002
- 5 - Revision A2
ABSOLUTE MAXIMUM RATINGS
PARAMETER RATING UNIT
Supply Voltage to Ground Potential -0.3 to +7.0 V
Applied Input/Output Voltage -0.3 to +7.0 V
Power Dissipation 120 mW
Ambient Operating Temperature 0 to +70 °C
Storage Temperature -55 to +150 °C
Note: Exposure to conditions beyond those listed under Absolute Maximum Ratings may adversely affect the life and reliability
of the device.
DC CHARACTERISTICS
(VDD−VSS = 3.0V, FOSC. = 32.768 KHz, TA = 25° C; unless otherwise specified)
PARAMETER SYM. CONDITIONS MIN. TYP. MAX. UNIT
Op. Voltage VDD - 2.4 - 5.5 V
Op. Current (Crystal type) IOP1 No load (Ext-V) - - 20 µA
Op. Current (RC type) IOP2 No load (Ext-V) - - 65 µA
Hold Current (Crystal type) IHM1 Hold mode
No load (Ext-V) - - 6
µA
Hold Current (RC type) IHM2 Hold mode
No load (Ext-V) - - 40
µA
Stop Current (Crystal type) ISM1 Stop mode
No load (Ext-V) - 0.1 2 µA
Stop Current (RC type) ISM2 Stop mode
No load (Ext-V) - 0.1 2 µA
Input Low Voltage VIL - VSS - 0.3 VDD V
Input High Voltage VIH - 0.7 VDD - VDD V
MFP Output Low Voltage VML IOL = 3.5 mA - - 0.4 V
MFP Output High Voltage VMH IOH = -3.5 mA 2.4 - - V
Port RA, RB Output Low Voltage VABL IOL = 2.0 mA - - 0.4 V
Port RA, RB Output high Voltage VABH IOH = -2.0 mA 2.4 - - V
LCD Supply Current ILCD All Seg. On - - 10 µA
SEG0−SEG23 Sink Current
(work as LCD output pins) IOL VOL = 0.4V
VLCD = 0.0V 0.4 - - µA
SEG0−SEG23 Drive Current
(work as LCD output pins) IOH VOH = 2.4V
VLCD = 3.0V -0.3 - - µA
W541C250
Publication Release Date: Feb 2002
- 6 - Revision A2
DC Characteristics, continued
PARAMETER SYM. CONDITIONS MIN. TYP. MAX. UNIT
SEG0−SEG23 Output Low
Voltage (work as DC output pins) VSL IOL = 0.6 mA - - 0.4 V
SEG0−SEG23 Output High
Voltage (work as DC output pins) VSH IOH = -0.3 µA 2.4 - - V
Port RE Sink Current IEL VOL = 0.9V 9 - - mA
Port RE Source Current IEH VOH = 2.4V -0.4 -1.2 - mA
Pull-up Resistor RCD Port RC, RD 100 350 1000 KΩ
INT Pull-up Resistor RINT - 50 250 1000
KΩ
RES Pull-up Resistor RRES - 20 100 500
KΩ
AC CHARACTERISTICS
(VDD−VSS = 3V, TA = 25° C; unless otherwise specified)
PARAMETER SYM. CONDITIONS MIN. TYP. MAX. UNIT
RC type - - 4000
Op. Frequency FOSC Crystal type 1 (Option
low-speed type) - 32.768 - KHz
Crystal type 2 (Option
high-speed type) 400 - 2000
Instruction Cycle Time TI One machine cycle - 4/FOSC - mS
Reset Active Width TRAW FOSC = 32.768 KHz 1 - - µS
Interrupt Active Width TIAW FOSC = 32.768 KHz 1 - - µS
W541C250
Publication Release Date: Feb 2002
- 7 - Revision A2
TYPICAL APPLICATION CIRCUIT
MFP
INT
RES
XOUT
XIN
DH1
DH2
RC2
RC3
RA0
RA3
Output Signal
RB0
RB1
RB2
COM0
COM3
RB3
RC0
RC1
SEG0
SEG23
RD0
RD1
RD2
RD3
LCD
PANEL
(1/3 Bias
1/4 Duty)
RE0
RE1
RE2
RE3
Connect to capacitor and VD
D
to generate LCD voltage
Vcc
Vcc
Vcc
VDD
VDD1
VDD2
VDD3
VSS
or
*1(option)
Note :
*1 is for accuracy
