Gotcha. Looks like I'm on IDF 5.1.1 and using the legacy driver. I will try the ESP_INTR_FLAG_IRAM as well as see if the problem persists with the newer I2C driver. Thank you!

The ESP is the I2C master. It seems like the delay causes the slave chips to not ACK the transmission which then errors out the ACK checks on the ESP side? This is not unexpected. Note that a) writes to flash can take a 'long' time, especially with SPIFFS, and b) during every write to the flash, mos...

Hi all I'm seeing some weird issues with I2C transmissions. Normally, everything works fine but sometimes, I'll see this behavior where there is a random 45ms delay mid-transmission which then results in a failure. See example below: I2C failure example.png I've seen this happen with both reads and ...