Casio WK-1200, Service Manual

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Pin No. Terminal In/Out Function
49 EOEB Out Read enable signal output for the effect RAM
50 VSS3 In Ground (0 V) source
60 BWEB 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
LCD DRIVER (LSI501 : SED1278F0A)
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 501.
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 forgenerating the stepped pulse of
the LCD drive signals.
31, 32 LP, XSCL — Not used
33 VDD In LVDD (+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