Power Fail Detection Circuit - Teknor Industrial Computers TEK-AT4LVG Technical Reference Manual

7.05.3 POWER FAIL DETECTION CIRCUIT

The Power Failure Detector monitors:
• The backup battery to warn of a low battery condition, and
• The +5V power supply to detect when it falls below 4.75V.
If either of the two above conditions occur, the PFO (Power Fail Output signal) goes low.
In turn, the PFO is connected to the IOCHK* line to generate a non-maskable interrupt
(NMI).
Power fail monitoring is enabled by using the W29 jumper. W29 is described in Section 4-
9 (Setting Jumpers).
Installing and Working With System Components 7-10