fmc operations cause mcu reset repeatly

[JJ.Lin]

Hi everyone,

I met a problem now. I am developing display product using stm32f429zet6, the lib is f41.26.1. In my project, nand flash is used to storage images and fonts, the sdram is used to cache images. Fatfs work upon nand. Obviously nand and sdram use fmc interface. When mcu start, I copy the images from nand to sdram before ui task stark. But in this operation, mcu would reset repeatly reset some times. Times is not fixed. Sometimes is 3 while sometimes is more, but sometimes it works well without reset. There is not mcu reset function in the copy process. I can't express why.

/JJ.Lin

[Tesla DeLorean]

Scope the power supply rail vs the NRST pin. Might also look for interconnected nets, inconsistent grounding, or circuitous routing of power

Any watchdog running?

[TDK]

Determine the cause of the reset by looking at the RCC->CSR register.

[JJ.Lin]

Thank you a lot! If it works well the CSR register show that it is reset by soft reset as is designed, but unexpected reset due to POR/PDR (power on/ down) reset. How can NAND flash or SDRAM read/wirte cause power reset? So how can I do next ?

[TDK]

> How can NAND flash or SDRAM read/wirte cause power reset? So how can I do next ?

They use power, perhaps they are using more than you have available, causing the voltage to drop, causing a reset. Monitor the rail with a scope. Create a power budget to ensure you can power everything off of the LDO you're using (or whatever power generation you have).