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IO14/IO15 boot conflict in SDIO Slave Mode

Posted: Sun Sep 06, 2020 2:21 am
by FreyaRose
I have the ESP32 running as an SDIO slave connected to a linux processor running as the SDIO host.

When I rest the ESP32, I get SDIO clock errors on the linux host.

I believe there must be some issue with the ROM bootloader in conflict on SDIO CMD (IO15) and/or SDIO CLK (IO14). Perhaps there is a strapping issue with these pins when the chip is reset into the ROM bootloader?

When I reset the chip using a deep sleep reset, I do not get these SDIO clock errors on my linux host. It is only on a EN toggle off then on.

Perhaps there is a fuse I can set to avoid this issue? Maybe this is a JTAG conflict?