ESP32 Forum

Hi everyone!

I'm new to this forum and am looking for some help. I am working with the ESP32-C3-MINI SoC for a PCB board. I need to have SPI and I2C communication to two devices (SPI to device one, I2C to device two).

I cannot devise a pinout for these, as most of the breakout pins appear to be used for the internal SPI flash memory.

Could anyone please help?

Best,

Sasha (ham radio callsign VE3SVF)

You can use any (not otherwise assigned/used) pin for SPI and I2C; the ESP32-C3 has a GPIO matrix that can route those signals arbitrarily.

Sorry for the late reply!

Does that mean that I can use *any* pin? I know there are many precautions around other ESP32 SoCs because sometimes the SPI flash is connected and some pins are used for strapping.

VE3SVF wrote: ↑

Sat Mar 16, 2024 9:36 pm

Sorry for the late reply!

Does that mean that I can use *any* pin? I know there are many precautions around other ESP32 SoCs because sometimes the SPI flash is connected and some pins are used for strapping.

Yep, hence my (not otherwise used/assigned) remark. Check the datasheet for the flash pins and don't use them, also check them for bootstrap pins and see if the restrictions on those are an issue. (Also note a fair amount of bootstrap pins only have an effect after some eFuse is burned; without that they're unrestricted.)

Sorry for my continued confusion.

By "flash pins," do you mean the USB+,USB- and RX/TX pins, used for flashing firmware?

Thank you for your understanding!

I mean the pins the (internal) flash is connected, again, check the datasheet. Aside from that, if you want to be able to re-flash your ESP32-C3, it's obviously good to also keep from using the pins you need to do that, yes.