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– 73 –
Pin No.
Pin Name
I/O
Description
68
VKK
—
Power supply terminal (–30V) (for fluorescent indicator tube drive)
69
VDD
—
Power supply terminal (+5V)
70
XIN
I
System clock input terminal (12.5 MHz)
71
VSS
—
Ground terminal
72
XOUT
O
System clock output terminal (12.5 MHz)
73
RESET
I
System reset signal input from the reset signal generator (IC502) “L”: reset
For several hundreds msec. after the power supply rises, “L” is input, then it changes to “H”
74
CH
O
Not used (open)
75
BUSY
I
Not used (open)
76
TEST
I
Connected to ground
77
—
—
Not used (fixed at “L”)
78
I2C DATA
I/O
Communication data bus with the system controller (IC501)
79
I2C CLK
I/O
Communication data reading clock signal input or transfer clock signal output with the system
controller (IC501)
80
—
—
Not used (fixed at “L”)