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Removal of Low Battery Message at Power Up



This is a request to change the AccuVote firmware code to disable (or delay) displaying or checking for a low power supply battery condition at power up.  Currently, this message occurs at power up even with the AC plugged in.  Some customers get anxious that their batteries are low, even though the condition does not exist.
 
We should never show a "BATTERY LOW" condition if the ACFAIL is false.
 
 
The following occurs within a couple of seconds from power up:
  • When powering up an AccuVote, the high capacitance on the 15V system takes a second or so to charge up.
  • The BATT LOW signal from the Power Supply is true while the 15V system is charging.  All this time, the ACFAIL signal is false.
  • While the 15V system is trying to reach its full voltage, the CPU starts executing code because the 5V system is already stable and the reset delay has expired (approx 500 msec).
  • The code appears to check the CPU's inputs, sees the BATT LOW is true, and displays a "BATTERY LOW" message on the LCD.
  • After the 15V system has charged past the BATT LOW threshold, the BATT LOW signal is now false.
  • The CPU no longer sees a true BATT LOW and therefore doesn't display the LCD message until the condition does actually exist or the next power up.