How does the battery / power-up check work on the PCD?

FAQ #101929

A 2,2 voltage of the battery is sufficient to keep the content of the SRAM memory of the PCD even if the PCD is not powered on with the 24VDC.

At power-up, the PCD checks if the battery or supeCAP voltage is less than 2.2. volt, and tests some patterns and signatures in the SRAM.

If one of those test gives an error the content of the SRAM is deleted, the PCD clock is reinitialized. If a Program Backup is available, a restore is done.

The entry "memory lost nn" is written in the History of the PCD where 'nn' stands for:

01: Bad or missing battery
02: Supercap voltage too low
03: Corrupted memory pattern/signature
04: RAM memory cleared by user (push button)
05: RAM and flash memory cleared by push button
06: Corrupted program header
10: Program restored due to CRC error
11: CRC error detected on program, but no backup was available for restore

Remarks

In older FW < 1.10.04 the error message in the history was "Media corruption" instead of "memory lost"
and the nn code was not implemented
New restore option since firmware version 1.20.00 and PG5 2.1:
On PCD2.M5xx0 and PCD3.Mxxx0, systems where the program is stored on SRAM, it is possible in the device configurator of PG5 to enable a CRC check.
The test is done over the program or the program and the ROM Texts/DBs.

In case of CRC error, the program is restored and the entry "memory fail 10" is written in the History of the PCD.
If there is no program backup, and therefore it's not possible to do the restore, the History entry "memory fail 11" will be written.

Related Files:

DC_101719.png

How does the battery / power-up check work on the PCD?

FAQ #101929

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