i2cDumpInts(): 0 row count INTR TX RX Tick i2cProcQueue(): Busy Timeout start=0x2a6, end=0x2ab, =5, max=5 error=1 The I2C code works, I believe the problem will be either bus hardware, or Slave SCL stretching. Enabling the Debug buffer would show the exactly the sequence were the timeout is occurring. The compile issue is an annoyance with IDF V4, but it is not his problem. I would debug it by actually monitoring the I2C bus with a logic analyzer. Either an other master is active or a Slave is pulling the bus low. Bus busy is set when the I2C peripheral sees activity on the bus that it is not generating. His original problem was a timeout, the timeout is occurring because the I2C peripheral is seeing a busy state on the bus, Either a Slave is doing SCL clock stretching that exceeds the 13.1ms max or his hardware has a problem. 3 change the code by removing the variable field width to a fixed width.2 fence out the format warning from the code.1 disable promoting the 'format warning' to an error.The problem that is seeing is 'Warning as Errors', I see Three possible solutions:

Arduino wire library warning