— 8 —
LCD DRIVER (LSI401: SED1278F2A)
The LCD driver can drive a dot matrix LCD having 40 segment and 16 common lines. The LSI contains 240
graphic symbols in the built-in character generator ROM, and stores 80 characters in the built-in display data
RAM. In accordance with command from the CPU, the LSI is capable of displaying up to 16 characters
simultaneously. The following table shows the pin functions of LSI 401.
Pin No.
Terminal
In/Out
Function
42 , 44, 46 ~ 48,
EA0 ~ EA12
Out
Address bus for the effect RAM
51 ~ 59, 61
45
ECEB
Out
Chip enable signal output for the effect RAM
49
EOEB
Out
Read enable signal output for the effect RAM
50
VSS3
In
Ground (0 V) source
60
EWEB
Out
Write enable signal output for the effect RAM
62, 66, 70, 74, 78
VSS2
In
Ground source
63, 67, 71, 75, 79
VDD2
In
+5 V source
64, 65, 68, 69,
PA0 ~ PA5
Out
Button scan signal output
72, 73
76, 77
PA6/7
Out
Not used
Pin No.
Terminal
In/Out
Function
1 ~ 22,
SEG1 ~ SEG40
Out
Segment signal output
63 ~ 80
23
VSS
—
GND (0 V) source
24, 25
OSC1, OSC2
In/Out
Terminals for the built-in clock pulse generator. The external
resistor connected determines the oscillation frequency.
26 ~ 30
V1 ~ V5
In
LCD drive voltage input.
Those voltages are used for generating the stepped pulse of
the LCD drive signals.
31, 32
LP, XCLS
—
Not used
33
VDD
In
DVDD (+5 V) source
34, 35
FR, DO
—
Not used
36
RS
In
Data/command determination terminal.
High: data, Low: command
37
R/W
In
Read/write terminal. High: read, Low: write
38
E
In
Chip enable signal.
High: enable, the writing is done at fall edge.
Low: disenable
39 ~ 42
DB0 ~ DB3
—
Not used. Connected to GND (0 V)
43 ~ 46
DB4 ~ DB7
In/Out
Data bus
47 ~ 62
COM1 ~ COM16
Out
Common signal/output
