TPS3435-Q1: WD-EN Pin control during flashing of MCU

Prahaladh S

Part Number: TPS3435-Q1

Hi...

We're planning to use TPS3435CECAJDDFRQ1 in our application to control the reset pin of TMS320S28377SPTPT.

When the MCU enters the flash mode, then it can't provide WDI which would lead to WDT pulling the reset of MCU down, continuously.

For this, we had planned to connect the TRST pin through a BJT to the WD-EN pin so that when the MCU is working (TRST-0), WD-EN would be high & WDT will work as usual.

When TRST is 1, MCU enters flash mode & at that time, the WD-EN will be made zero i.e. WDT will not have control over the MCU reset during flashing.

Kindly let me know your views on this implementation.

Best Regards,

Prahaladh S

7 months ago

+1 Joshua Garcia 7 months ago

TI__Genius 15180 points

Hi Prahaladh,

Having an external control to disable WD-EN during flashing is the intended use. As you mentioned while WD-EN = 0 (low state) the watchdog will be disabled and the WDO will remain unasserted (high).

Thanks,
Joshua

0 Prahaladh S 7 months ago in reply to Joshua Garcia

Intellectual 350 points

Thank you Joshua for your response. This would help us...

0 Prahaladh S 7 months ago in reply to Joshua Garcia

Intellectual 350 points

Dear Joshua,

We would have an external control for the WD-EN pin. For that, we are thinking if we can give the TRST pin of TMS320F28377SPTPT for the WD-EN. The logic levels, we'll check i.e. if inversion is required, we can do.

Kindly let me know your views on this...

Best Regards,

Prahaladh S

0 Joshua Garcia 7 months ago in reply to Prahaladh S

TI__Genius 15180 points

Hi Prahaladh,

Given the TRST can drive the WD-EN and the levels align such that the watchdog is disabled during your flashing time and enabled when you want normal operation I see no concern.

Thanks,
Joshua

0 Prahaladh S 7 months ago in reply to Joshua Garcia

Intellectual 350 points

Dear Joshua,

Thank you for your response.

Best Regards,

Prahaladh S

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TPS3435-Q1: WD-EN Pin control during flashing of MCU