STM32DDRFW-UITL Custom Board Errors with "Unknown Command"

[m_stoko]

I'm attempting to modify STM32DDRFW-UTIL to test my DDR on a custom board, but when I try to connect via putty I get a continuous loop of error codes "Unknown command" without ever typing anything into the console. I noticed that the console header seems to be appearing on the input line (see attached photo). I can't figure out if this issue is caused by an incorrect DDR setup on my side or something more on the hardware side (i.e. something I don't know). Any input would be appreciated, thanks!

[js214]

In what ways did you modify the DDRFW-UTIL? Feel free to compare with my version of it: https://github.com/js216/stm32mp135_test_board/tree/main/baremetal/STM32DDRFW-UTIL 

Since the UTIL does not run out of DDR, your problem is unlikely to be caused by DDR misconfiguration. Are you able to run a basic "Hello, world!" program on your board? Examples are available in the STM32CubeMP13 Package (instructions here).

[PatrickF]

Hi,

Maybe look at UART_RX HW, there might be some unwanted toggling or bad level detected by the UART.

Did you use a FTDI like UAB<->UART cable ? is the voltage correct ?

Regards,