Unable to use I2C sensors with ESP32-C3

jamesyoung · Postby **jamesyoung** » Wed Aug 28, 2024 5:13 am

Hello,

I am using an ESP32-C3 Super Mini board. I am unable to read from any attached I2C devices. I have connected them to a Raspberry Pi and they show up under i2cdetect and I can read and write from them with no issues. I have also tried an ESP32 board, and they work fine, however I cannot seem to make them work on the ESP32-C3 Super Mini. I have connected the sensor (PCT2075D) to pins 8 and 9 (SDA and SCL). I then ran a sketch pct2075_test.ino (https://raw.githubusercontent.com/adafr ... 5_test.ino) to test it, but it cannot see the sensor. I then tried running WireScan.ino (https://raw.githubusercontent.com/espre ... reScan.ino), and this also does not show any devices found. I connected my logic analyzer to the port, and it can see write activity from the ESP32-C3 Super Mini, but it does not show any devices connected. Attached is a screenshot of the capture. I have 3 of them, and none of them want to work with I2C. I have also tried different board options in Arduino, including Adafruit QT Py ESP32-C3, Geekble Mini ESP32-C3 and ESP32C3 Dev Module.

Any help would be greatly appreciated!

lbernstone · Postby **lbernstone** » Wed Aug 28, 2024 4:06 pm

The esp32 is a 3V3 device. Make sure all your signals are at 3V3, and have pull up resistors also connected to 3V3. Note that pin9 is the boot pin, so the pull up must be weaker than the path through the boot button.