Changing I2C pins

itsMeBrice
Posts: 2
Joined: Thu Mar 14, 2019 1:25 pm

Changing I2C pins

Postby itsMeBrice » Thu Mar 14, 2019 2:07 pm

I'm trying to test different Peripheral Protocols simultaneously (I2C, SPI, SDCard) to run on an ESP32-Wroover-Kit-v3.
I've got all of them running independently but stumbled upon a problem which i can't seem to be able to fix.
I've used the i2c_self_test example to test the I2C capabilites and subsequently tried to change the pins from the default ones (because i use the default pins for the VSPI Controller.
The example runs just fine with the default pins but when i change them i herAccording to different resources this should be possible and a non-issue.
But once i change the pins for the example, all i get is the following error:
  1. W (1304) i2c-example: TASK[0] ESP_FAIL: Master read slave error, IO not connected...
  2. W (2304) i2c-example: TASK[0] ESP_FAIL: Master write slave error, IO not connected....
  3. W (2304) i2c-example: TASK[1] ESP_FAIL: Master read slave error, IO not connected...
The only difference to the working default example being the change of the slave SCL GPIO_PIN from 19 to 17.
Can somebody help me resolve this issue?
Thanks in advance.

ESP_Sprite
Posts: 2759
Joined: Thu Nov 26, 2015 4:08 am

Re: Changing I2C pins

Postby ESP_Sprite » Fri Mar 15, 2019 2:45 pm

GPIO 16 and 17 are used by the PSRAM on -Wrover modules and as such not available externally. Please pick different ones.

itsMeBrice
Posts: 2
Joined: Thu Mar 14, 2019 1:25 pm

Re: Changing I2C pins

Postby itsMeBrice » Mon Mar 18, 2019 8:24 am

Thanks for the reply, after some further trial and error I found pins on which it works (22/27).
I checked on the schematics for pin freeness and found pins i wanted to use (32/33) and they seem free and usable. Upon testing though they do not work. Any tipps?
Is there some full list on pins which can't /shouldn't be used for additional peripherals?
Thanks again!

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