We are having 6 proto boards and out of 6 boards only 3 are working properly, I'll outline my observations:
Similarities:
- All six boards can be programmed/erase the flash.
- Physically, the orientation of all components is the same for every board.
- Each board has a proper clock and reset.
- The BOOT0 pin is pull-downed on all boards.
- All boards show the same VCAP pin voltage (1.3V).
Differences:
- In working three boards, the board is working as expected, but in the other three, it seems it is not running the program.
- The overall current consumption of the working board is about 20mA, while the non-working boards have an overall current consumption of about 9mA.
Actions taken on the boards:
Tested a LED blinking code with an external clock configuration and debugged it on both boards:
- Previously working board's LED is blinking as expected.
- Previously non-working board's LED is not blinking.
Used the same code with an internal clock configuration and debugged it on both boards:
- Previously working board's LED is blinking as expected.
- Previously non-working board's LED is blinking.
After identifying that the problem lies with the system clock, we exchanged the crystal and load capacitors between a working board and a non-working board. However, we still obtained the same results as mentioned above.
This is the non functional board's Main crystal clock out. it seems the clock is working but the controller not taking the clock, something wrong with the controller
Please, can anyone help me identify this problem and suggest possible solutions?
Hi @SofLit,
Our revision is X, and we found a problem that is neither related to the MCU nor the main crystal (HSE). It is associated with the RTC crystal (LSE). When we remove the load capacitors of the RTC Clock, it works every time. Thank you for your support, ST; your assistance means a lot to me.
