Pin No.TerminalIn/OutFunction
74 ~ 77DB4 ~ DB7OutData bus for the LCD driver
78NC9NNot used
79LVCCIn+5 V source
80 ~ 84KO8 ~ KO12OutTerminals for button scan signal
85 ~ 87P65 ~ P67NNot used
88RSOutControl signal for the LCD driver
89R/WOutRead/Write signal for the LCD driver
90EOutChip enable signal for the LCD driver
91 ~ 95P73 ~ P77NNot used
96LGNDInGround source
97, 100MA18, MA15OutAddress bus
LCD DRIVER (LSI3: 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 LSI3.
Pin No.TerminalIn/OutFunction
1 ~ 22,SEG1 ~ SEG40OutSegment signal output
63 ~ 80
23VSSNGND (0 V) source
Terminals for the built-in clock pulse generator. The external24, 25OSC1, OSC2In/Out
resistor connected determines the oscillation frequency.
LCD drive voltage input.
26 ~ 30V1 ~ V5InThose voltages are used for generating the stepped pulse of
the LCD drive signals.
31, 32LP, XCLSNNot used
33VDDInDVDD (+5 V) source
34, 35FR, DONNot used
Data/command determination terminal.36RSIn
High: data, Low: command
37R/WInRead/Write terminal. High: read, Low: write
Chip enable signal.
38EInHigh: enable, the writing is done at fall edge.
Low: disenable
39 ~ 42DB0 ~ DB3NNot used. Connected to GND (0 V)
43 ~ 46DB4 ~ DB7In/OutData bus
47 ~ 62COM1 ~ COM16OutCommon signal/output
N 5 N |
ACEC
CASIO
