1541 CIRCUIT THEORY
The Reset Circuit
The output of the exclusive 'or' gate UD3 pin 6 will be "low” until C46 has charged through R25.
Once the voltage across C46 reaches 2 volts, the output of UD3 pin 6 will go "high". This occurs
when the disk is powered on, or a reset pulse is generated by a device connected to the serial bus.
The reset pulse on the serial bus interface is input on, pin 6 of P2 or P3. This "low" to "high" going
pulse on pin 6 of UD3 is input to the microprocessors reset interrupt input. This causes a restart or
reset routine to be executed giving control of the disk drive operation to the Disk Operating System
(DOS).
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