Hi!
I designed a shield for the Nucleo-144 (F429ZI) which provides power to the Nucleo-144 board through the E5V pin.
To configure the board, I did the following:
- Place JP3 E5V
- Remove JP1
- Remove JP6
- Remove JP7
- Open SB169
- Close SB115
I disconnected the ST Link part by removing diode D3.
After a small modification to the NRST pin (which is somehow pulled low through the ST Link when turned off), the CPU runs.
It uses the 32 kHz oscillator though, because the ST Link normally provides the high speed clock through the MCO pin.
As soon as I connect diode D3 and LED LD4 starts blinking it seems to pull quite a lot more power (in such a way that it destabilizes the power supply).
Connecting diode D3 and removing JP5 (basically turn off the STM32) also gives a stable situation.
It seems that there is some leakage current going between the STM32 and the ST Link when both parts are powered via the E5V pin.
Does anyone have an idea what is going on here?
And what is the proper way of setting up the Nucleo-144 for powering from the E5V pin?
Thank you in advance!
