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Hi,
I had followed eZdspTM F28335 design for powering up TMS320F28335SPTPQ in my product. It is the first time power up of my board.
As per the IC functionality, reset time out is 200ms. In my design initial power up sequence is fine. But after that, reset is not stable. It has to be at 3.3V constantly but it is toggling at a period of 4.5 ms.
Signals is like 4.5ms at 3.3V level and 15uS at 0V level and again goes to 4.5mS at 3.3V level.
Please help me to resolve the issue.
Hi Kyle,
Thanks for the reply.
I have monitored the power rails and found OK. I suspected power rails initially, but if it is so there must be reset time out of 200ms gap. but in my case it is only 15uS and later 4,5mS. I attached schematics. Please reply.
Hi Kyle,
I'm sorry for delayed response. I could not share waveform with TI since I didn't capture them. But I found the answer i believe. It is due to internal watch dog timer. WDT is setting it to low 15uS. Once I gave trst# high, I could see clean reset signal. Thank You so much for supporting.