Olimex Support Forum

Microcontrollers => ESP32 => Topic started by: champ8242 on July 23, 2023, 01:19:15 PM

Title: I2C device not found
Post by: champ8242 on July 23, 2023, 01:19:15 PM
Hi,
Just received a ESP32-GATEWAY and need to use other than standard I2C pins.
As a simple test to change pins and an I2C device (BME280) I have I have used the simple
Arduino INO sample from Random Nerd Tutorials. Click here for code (https://randomnerdtutorials.com/esp32-i2c-communication-arduino-ide/)

I have changed the sample pins
#define I2C_SDA 33
#define I2C_SCL 32
To
#define I2C_SDA 16
#define I2C_SCL 32

When I run it on the ESP32-GATEWAY, I get: "Could not find a valid BME280 sensor, check wiring!"

When I move the code and device to a ESP32 Dev Kit it runs perfectly.

Looked over and over that I used the right pins but all looks OK

Anybody with a suggestion?
 
Title: Re: I2C device not found
Post by: LubOlimex on July 24, 2023, 08:19:13 AM
16 and 32 seem free to use. Probably something in the software or the wiring. You usually don't need to redefine SDA and SCL if you have selected Olimex ESP32-GATEWAY from the board selection menu, they are already set here:

https://github.com/espressif/arduino-esp32/blob/master/variants/esp32-gateway/pins_arduino.h

static const uint8_t SCL = 16; // This is extention pin 11
static const uint8_t SDA = 32; // This is extention pin 13

Double check the wiring if the proper pins are identified.

Consider if you need to add pull ups on the I2C lines.
Title: Re: I2C device not found
Post by: champ8242 on July 24, 2023, 12:18:19 PM
Totally my mistake!. I used the BME280 on the ESP32-GATEWAY 5V where I should have used it on the 3.3v. Sorry!