Hello. We made our board for the CM3 module. But, they did not connect pin 76(GPIO0_A4) to the GND. This pin is used as sdcard0-detect. This is necessary for the module to work with the SD card. This pin is configured as a pull-up input. Naturally, there is always 1. I can’t solder to 0, very small contacts. Tell me, how can I programmatically make pull down?
CM3 module. Pull down pin
The raspberry pi cm4 doesn’t have sd card detect because either you use eMMC, or you use SD card for the OS. You can not use both at the same time.
For Radxa CM3, eMMC and SD card can be used at the same time. If your hardware doesn’t have SDMMC0_DET_L connected, you can not hotplug the SD card but if the SD card is there before power on:
If the SD card has bootable images, you can boot and running from SD card. If the SD card is not bootable, you can boot from CM3 eMMC, and SD card is also detected. You can not hotplug it.
Unfortunately, it is not. This output SDMMC0_DET_L must be connected to GND. When it is not connected anywhere, the SD card is not in the system. A batch of printed circuit boards has already been made. That’s why I’m looking for a software solution.