Front Panel Control Circuit

The following small piece of circuitry is attached to the manual control buttons and switches on the front panel. All of the pushbuttons are connected to pulse formers so that they produce 1-tick pulses. The Start, Load Address, Deposit, and Examine buttons are additionally gated with the /RUN signal so that they only operate when the machine is halted.

The Start, Continue, Load Address, Deposit and Examine pulse signals are wired-OR connected to the CONTP* line so that they start the machine running.

The Single Cycle and Single Instruction switches are connected through inverters so that they are active in the up position. Single Step asserts STOP*, which causes the machine to stop at the end of the current cycle. Single Instruction asserts STOPRQ*, which causes the machine to stop at the end of the Execute cycle of the current instruction.