[Resolved] TwoWire _wire = TwoWire(1); causing NULL TX buffer pointer error

PlatformIO IDE
1

Microsoft Windows 11 Version 22H2 (OS Build 22621.4249)
PlatformIO Core 6.1.16·Home 3.4.4 ( airm2m_core_esp32c3 board selected )
ESP32-C3
Zadig 2.9 (Build 788)
FTDI driver CDM212364_Setup

The instruction of TwoWire(1) caused error message below at the line of .beginTransmission():

[ 89][E][Wire.cpp:448] endTransmission(): NULL TX buffer pointer

The code:

void scan (void)
{
    Serial.println("Scanning for I2C devices...");
    for( uint8_t address = 1; address < 127; address++ ) 
	{
    _wire.beginTransmission(address);
    uint8_t error = _wire.endTransmission();
    if( error == 0 ) 
	{
    Serial.print("I2C device found at address 0x");
    if (address < 16) Serial.print("0");
    Serial.println(address, HEX);
    }
    }
    Serial.println("I2C scan complete.");	
}

However, if I specify as “TwoWire _wire = TwoWire(0);” then no error, able to detect the I2C device address.

Please advise.

2

What happens if you use the already existing Wire object like the WireScan example does?

3

using Wire. is fine as TwoWire(0), the TwoWire(1) created the error mentioned.

4

The ESP32 has two I2C interfaces, but the ESP32-C3 has only one of them.

ESP32 datasheet | page 4 | Advanced Peripheral Interfaces
ESP32-C3 datasheet | page 4 | Advanced Peripheral Interfaces

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