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'core held in reset' issue

Bruce Brealey
Associate
Posted on January 24, 2018 at 09:58

Hi I'm using the STM32F745VE on a Product.

I have been using a nucleo board (with ST link utility) to program the product via SWD connector (3V3 provided separately) which has been fine so far.

I am now at our suppliers site with the same lap-top, cables and nucleo PCB but when I try to 'connect to target' on their PCBs its takes a long time then gives 'Cannot connect to target'. Once OK is pressed the message in the bottom pane of ST-Link says 'core held in reset'

When I probe the reset pin on the target PCB it is 0.8V. This is the same whether the Nucleo is connected to the Lap-top or not. If I disconnect the Nucleo from the target PCB its reset pin returns to 3v3.

What I would like to know is if the nucleo should pull the reset down like this or is it broken? it was in an aircraft hold for 10+ hours. I don't think its the target PCB but this is the only thing that is different.

Many thanks

Bruce.

1 REPLY 1
Posted on January 24, 2018 at 15:47

Review the custom circuit.

Confirm VDDA connectivity. Check VCAP voltage and caps as placed.

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