how to use the crystal on osc_in and osc_out with stm32mp157

[SChen.11]

Hi everyone, I designed a custom board . It use 24MHz crystal instead of oscillator with stm32mp157. Now, I follow the wiki page to modify the clk_hse with "st,bypass;" in file arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi .

But the board always can not boot up. Did I missing something?

The wiki page that I referenced. https://wiki.st.com/stm32mpu/wiki/Clock_device_tree_configuration_-_Bootloader_specific

[PatrickF]

Hi,

Did you ever have any console message ? If yes, please provide the log.

Are you able to 'boot' over USB (with a PC connected on OTG_HS_DP/OTG_HS_DM) using BOOT[2:0] = 0b000 (or 0b110) ? If yes, this mean you crystal is connected right and you might have SW setting issues.

To exclude other issues (Resets, supplies, crystal oscillation, etc..), you could also try to startup the board with injecting an external square clock on OSC_IN (PH0) while OSC_OUT (PH1) is tied to GND.

[SChen.11]

Thanks for your guide. I will check it again.​