TMS320F28062: Accidentally Reset regularly issue

Zhihong Huang

Part Number: TMS320F28062

Hi team

First time we discovered this Reset regularly issue, we changed the chip and downloaded the software again (without changing the system board).the whole system board was working normally without put into end equipment(motor control box in air conditioner).

However, the reset issue happened again after we put the system board into the end equipment(motor control box in air conditioner).

After removing the low-voltage reset chip in the system board, we monitored the 3.3V and XRS pins. The waveform is as follows: (it can be seen that XRS has the regular pull-down waveform issued by the chip) it is determined that the chip is repeatedly reset.

The green line is XRS PIN, and the blue line is 3.3V VCC PIN. Could you help me analysis why does this happen?

over 6 years ago

0 Zhihong Huang over 6 years ago

TI__Intellectual 1550 points

Here is the enlarge waveform:

0 Hareesh Janakiraman over 6 years ago in reply to Zhihong Huang

TI__Guru* 95315 points

Zhihong,

My first thought was that this was due to the watchdog. However, the pulse width and the frequency suggests otherwise. Please try this: Erase the flash and power-up the board. The WD will time-out and keep resetting the part forever. The width of the pulse should be around 51.2 uS (512 x 10nS) and the frequency should be around 76 Hz [10 MHz / (512 x 256) = 76.29 Hz or 13.1 mS]. If you observe this, that tells us that the WD is working the way it should.

Is the WD enabled in the application?

You mention that on a board where the MCU was replaced, you started observing the resets after the board was put into the end equipment. If the board worked fine outside the end equipment, but started exhibiting this behavior after it was put into the end equipment, it could be an event external to the board. Is there any event in the system occurring at the frequency at which the resets are seen?

Could you share the schematics of the board with me privately?

0 Hareesh Janakiraman over 6 years ago in reply to Hareesh Janakiraman

TI__Guru* 95315 points

Any updates on this?

0 Hareesh Janakiraman over 6 years ago in reply to Hareesh Janakiraman

TI__Guru* 95315 points

Closing due to inactivity.

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TMS320F28062: Accidentally Reset regularly issue