Why STM32F746xx hung up?

[Anton1]

Hello everyone,

I apply STM32F746BE with externel SDRAM and externel FLASH, Ethernet, LCD, I2C1, USART1, USART6. I-Cache and D-Cache disable.

Bootloader located in the internal ROM configures SDRAM and QSPI in memory-mapped mode, then launches firmware from externel FLASH.

Problem is microcontroller at a random moment in time hung up. And in this state, it is not possible to connect to the microcontroller via either st-link or j-link.

What can lead to this situation?

Thank you,

Anton

[waclawek.jan]

Clock failure? Some form of sleep? Program changing AF or MODER of SWD pins?

Use traditional methods to trace the program - LED blinking, debug printouts through whatever channel is available, etc.

JW

[ADior.1]

Hello, Jan

Anton is my colleague. Thank you for your answer.

We had configured output pin to show SYSCLK and when processor hags SYSCLK continues to tick as before.

We have enabled JTAG in sleep mode in Debug configurations. It didn't helped.

And we used MPU to protect PIN configurations, but the program still would hang.

Any thoughts on how to debug this situation without LED blinking? How to know what processor state is?

We have rtems OS and it could be hard to catch this bug with LED, but we are already trying. Rtems has fault handlers and they are not executing.

Regards Andrey.