FMC initialising and RTC desactivation

HamedAth · ‎2025-03-19

Dear All,

I designed a HMI board with STM32F767 and QSPI NOR flash and MT48LC16M SDRAM with external OSC 8MHz and MC-306 32.768 KHz.

Approximately I tested more than 100 PCs of this board and all work without any problem.

but during this week in some new boards, I saw when I initialise FMC, the RTC does not work anymore. even with RTC again initialising, it still doesn’t work and need to get restarted or power off.
I also tested with internal LSI but nothing changes. I also connected V BAT to VDD the problem is still there.
funny thing that this software works in many of these boards, but some of them have exactly the same problem.
I also removed the SDRAM and NoR flash chips, but again had same problem.
Any body have had this problem?

mƎALLEm · ‎2025-04-02

Hello,

Not obvious to tell what the problem is as there is no relation between FMC and RTC. You need to start a debug session and check where it fails in your code. Check all the return HAL APIs especially those of the RTC it may indicate the fail.

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