ESP32 Forum

Hi All
I am using the ESP32-C6-MINI-1U-H4/H8 module and I need some advice on IO pin selection for some external hardware on my new board.

I need to add an external Ethernet device (Wiznet W5100S module or similar) with a SPI interface and a second I2C interface.

I am currently using both UARTS (IO4, IO5 and TXD0, RXD0) and one I2C (IO6, IO7).
I also use most of the modules available IO pins.
I am able to reallocate IO's at the moment.

My planned connectons for the external SPI device are:
IO18 - MOSI
IO19 - MISO
IO21 - SCLK
IO22- INTn
IO23 - CSn

Will this selection work?

Which IO's would or should I use for a second I2C bus?

Many thanks
BJ

should I use for a second I2C bus?

ESP32-C6 has 2 I2C controller(s) (also called port).
one in the main system and one in the low-power system
We can't use I2C_NUM_1.

Hi
Thank you for your reply.
So I cannot have 2 external I2C busses on the ESP32-C6?
I hope this is not a stupid question, if so please forgive me.

I have three identical (3) I/O Expander IC's and they have only 1 address line (2 x I2C addresses) so I need a way to add the 3rd one hence the 2nd I2C.

Any thoughts on the SPI query?

Keep well
BJ

So I cannot have 2 external I2C busses on the ESP32-C6?

We can use only one hardware i2C.
We can use this as a second I2C.
https://github.com/espressif/esp-idf/tr ... o/soft_i2c

ESP32 can use all GPIO as SPI.