150-357-200-02, Issue 2
Overview
HXU-357 List 1
February 9, 1999
11
Watchdog Timer
If the watchdog timer does not receive a strobe pulse within 200 ms, a
time-out condition occurs, resulting in a hardware reset. The watchdog timer
also provides two other vital functions:
•
power-up hardware reset during power-up conditions
•
voltage monitoring that indicates when the +5 Vdc falls out of tolerance
(+/-0.5 Vdc).
Real Time Clock
The Real Time Clock (RTC) is supported through the Serial Communication
Port (SCP) on the microprocessor. The SCP consists of independent transmit
and receive section and a common clock generator. A serial alarm RTC
provides a full Binary Coded Decimal (BCD) clock calendar.
DC-to-DC Converter
The HXU-357 accepts two inputs of -48 Vdc from the A and B battery
supplies. Both the supply and return lines have isolated fault paths. The
converter supplies the p5 Vdc for the HXU-357.
