H743Zi2 Board

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Joined: 13/10/2014
Location: Australia
Posts: 715
Posted: 09:06am 03 Jul 2019      

Now that I know what I'm chasing, I tested the 2nd ZI2 bare board (no connectors soldered on yet) and it's exactly the same, no reset at power on.

Fortunately my breakout board has every inside pin connected, I placed a link on the board to select or deselect a 22uf cap running from reset to GND, reset delay is around a second with the link connected. This will do for now until the correct answer is found.

To recap, two new ZI2 boards do exactly the same thing -> NO reset - the old ZI has a reset delay.

Because I've been testing without a Screen up until today I always had it powered from the USB port during testing, the boards work correctly when the USB in connected as some part of the ST-LINK controller does a reset when EXT 5V is connected, OR, if the USB connector is plugged into the PC after EXT 5V has been connected. Edited by KeepIS 2019-07-04
It's all too hard.