IMX8MM can't run.plz help me to solve the case.

[Daria_cc]

The PMIC output is normal, and the 32k and 24M clock has started to oscillate, but the IMX8MM does not run because the USB serial download mode cannot be recognized. We also tried to boot directly with the SD card, but it was also not recognized. The oscilloscope measured data0 and clk without waveform output. Please help analyze the possible reasons, thanks.The schematic diagram has been attached, please refer to

[igorpadykov]

Hi Tina

for usb issue one can check 24MHz signal with oscilloscope, usb failure may be due to

clock instability. Also recommended to attach jtag debugger and try to test processor, like toggle gpio.

Best regards
igor

[Daria_cc]

I don't think it's the USB problem, it feels like the CPU is not working. But the clock and voltage are normal, so I don't know how to locate the problem.

[Daria_cc]

The waveforms at both ends of the 24M clock feedback resistor are shown in the attached picture. Help to see if it meets the stability requirements. The part number of our crystal is FA-128, and the manual has attached accessories. It is a pity that I did not reserve the JTAG interface so I cannot test it. Is there any other direction to solve the problem that can be provided?