wire1 not defined compilation error with ESP32C3

[pf26]

Using ESP32C3 dev module, the compiler fails in SSD1306Wire.h (library Version 4.6.1)
line84 this->_wire = (i2cBus == I2C_ONE) ? &Wire : &Wire1; ---> undefined Wire1

Workaround:
#undef ARDUINO_ARCH_ESP32
#define ARDUINO_ARCH_ESP8266 1
#include "SSD1306.h"
#define ARDUINO_ARCH_ESP32 1
#undef ARDUINO_ARCH_ESP8266

Defining ARDUINO_ARCH_ESP8266 is necessary to use alternate I2C pins.
ESP32 Board library V 2.0.18
ESP32 library V 3.2.0

I am quite new to all that, so it might be an issue on my side..

[marcelstoer]

I don't think there's a bug in this library. You can simply pass the SDA & SCL pins to the SSD1306Wire constructor.

If your hardware really has two I2C interfaces you should get Wire1 intitialized thanks to the ESP32 Arduino lib as per https://github.com/espressif/arduino-esp32/blob/master/libraries/Wire/src/Wire.h#L148-L150. To use the second you'd also need to pass I2C_TWO to the constructor.

[pf26]

Thks for prompt reply.
If I just use #include "SSD1306.h", it will not compile, because Wire1 is not defined.
Wire1 should be defined in wire.h (line148+), but as SOC_I2C_NUM is one for ESP32C3, Wire1 is not defined there.

#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 4, 0)
#if SOC_I2C_NUM > 1
extern TwoWire Wire1;

Maybe I am missing something else.

[marcelstoer]

it will not compile, because Wire1 is not defined.

You can pass i2cBus = I2C_ONE in the SSD1306Wire constructor which is the default anyway. Then this->_wire = (i2cBus == I2C_ONE) ? &Wire : &Wire1; at line 84 will evaluate to Wire rather than Wire1.

[pf26]

Thks for blazing fast support, but it is somewhat frustrating to see this issue closed when it is still open for me :
passing i2cBus = I2C_ONE in the SSD1306Wire is the default and has little effect as mentioned. Still the compiler get stuck, as the variable Wire1 is undefined. I understand the compiler could optimize and remove this code line but is not the case for me.

[nicop4]

Hello
As I could not implement the suggested solution, I forked the lib and fixed the initialization od the i2c interface when building on ESP32C3.

While waiting for the author to include the changes in a future release, it is possible to target my repo which is based on the main branch as of today, and which include the fix for ESP32C3.

This issue should be reopened in the meantime.

[marcelstoer]

Fixed with aa10104.