Technalogix TAV-1000, Руководство пользователя

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VI-6
Microcontroller Components
The heart of the monitor and control system found in Series IIH PCBs is microcontroller U14. This
microcontroller analyzes all RF power levels and voltages to ensure that all operating parameters are within
their predetermined safe operating levels. If a fault is found, appropriate action is taken to help protect the
system from damage, which may include turning the RF carriers off. A full description of all faults and their
respective actions is found later in this section.
The power supply for the microcontroller is monitored closely via supervisor U13. Should the +5Vdc supply
drop below +4.5Vdc, a microcontroller reset is generated to ensure there are no brown out conditions that
may latch up the microcontroller up to an unknown state. The front panel Reset momentary switch is also
tied to this line after optoisolation. The microcontroller’s clock source (4.000MHz) is generated by ceramic
resonator CR1. If the software is running, LED D12 will be lit. Finally, U15 stores all characters for the LCD
to minimize the overhead required for the microcontroller, and also stores the current state of the power
ON/OFF of the system. This ensures that, in the event of a power outage, the system returns to the exact
state is was before power was interrupted.