3
Theory of Operation
3.1
Block Diagram
The block diagram shows the basic design of the 8712. The microprocessor
reads the input mode bits when power is turned on and selects the input
interface. It also flashes the firmware version number on the internal red
LFAULT indicator. To check the firmware version, one has to count the
number of led flashes. There is a longer pause between the significant
number and the decimal number. For example, version 1.5 will flash the
LED once, followed by a pause, then will flash the LED five times.
Pulse and direction inputs (voltage or logic edge) from the selected interface
cause the microprocessor to generate low voltage Picomotor drive
waveforms. The output amplifier increases the amplitude of the drive
waveform sufficiently to drive the Picomotor. An internal power supply
generates the high voltage power for the output amplifier as well as other
supply voltages.
Block Diagram