Question about SYSESR EXTRST Bit in TMS570LS0432 device

Pashan None

Genius 5660 points

Other Parts Discussed in Thread: TMS570LS0432

Hello Support,

In the TMS570LS0432 device, I erased all the Flash Area.

Then I power cycle the supply to the board.

Then connected Code Composer and dumped address 0xFFFFFFE4 [SYSESR Register].

I see the SYSESR value as 0x8008 instead of 0x8000.

Please confirm why am I seeing EXTRST Bit when there is a Power Cycle.

Thank you.

Regards

Pashan

over 12 years ago

0 Chuck Davenport over 12 years ago

TI__Guru 59540 points

Hello Pashan,

I will have a look at this question and get back with you soon.

0 Eric Best over 12 years ago

TI__Expert 7255 points

Hi Pashan,

This is actually the expected behavior. Please see section 4.3 of the LS0432 datasheet (SPNS186). The warm reset nRST signal is bidirectional. On a normal nPORRST event, the internal circuitry drives this signal low and you will see 0x8008 in SYSESR. This can be verified with a scope probe on the nRST (and nPORRST) pin.

Regards,
Eric

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Question about SYSESR EXTRST Bit in TMS570LS0432 device