CRT display clock oscillator I/O pin.
Oscillator frequency is determined external L, C circuit.
System clock oscillator crystal connection pin. When using an external
clock, input to EXTAL pin and leave XTAL pin open.
"L" level active system reset. This pin also acts as an I/O pin during
power up. While internal power-on reset function is talking place a
"L" level is output.
Test mode input pin. Must be connected to GND.
Positive power supply pin for incorporated PROM writing.
Under normal operating conditions, connect to V
Positive supply voltage pin.
GND. Both Vss pins should be connected to common GND.
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