I have a problem where the PocketBeagle does not boot from MMC when plugged into my baseboard. Since this is all prototype hardware, I have spent hours troubleshooting, and I believe my problem is I have an ADC attached to SPI0, and the PocketBeagle tries to boot from SPI0. If I read SYSBOOT properly, the 5 LSbs of the PocketBeagle at 11000, and the AM335X datasheet indicates the boot order is SPI0, MMC0, USB0, and then UART0. I don’t want to boot from anything other than MMC0. The ADC is certainly not going to produce bootable code, but the boot process does not appear to move on to the next device if it gets a response. What to do?
I’m going to answer my own post. The thing I can do is keep the ADC in reset until after boot, and that does at least allow the PocketBeagle to start up. I never dreamed someone would actually want to boot from SPI much less that it would be the preferred boot device.