TM 5-6675-316-14
(4) Clock interface. This circuit takes the 1 kHz clock output from the
motherboard and generates the 500 and 250 Hz signals required for the stepping motor
circuits.
(5) Power on reset. This circuit determines whether an interrupt has been
caused-by power turn-on or by RESET key depression. This allows the program to
determine if RAM data must be reloaded.
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