Regarding Nordic Restart due to uart Baudrate Mismatch

[Naveenkumar]

Hi,

We are trying to establish communication between ESP8266 and NRF52832 over uart  using Baudrate 115200, We are also controlling the ESP8266 boot and power through GPIO from Nordic.  While enabling the ESP ,it Sends some boot Logs Over UART in the baud rate of 74880 , at this stage, Nrf is getting  restarted

Is there anyway that we can resolve this issue ?

Does changing the Nrf baudrate to 74880 will resolve ?  if so how can we proceed in this..?

[Turbo J]

Check VCC on an oscilloscope. Powering the ESP might cause the POR glitch, which triggers when VCC changes of ~0.5V occur too quickly.

Baud rate issues would cause a framing error - but this should be caught in a debugger.

[Naveenkumar]

how can we use the baudrate 74880 in nrf52832?

[Simonr]

Hi

This post explains how to calculate custom Baud rates. Keep in mind that a maximum of 3% deviation is acceptable for it to be a usable Baud rate.

Best regards,

Simon

[awneil]

Note that some (many?) of the Nordic examples treat a UART framing error as a fatal error ...

eg, see: https://devzone.nordicsemi.com/f/nordic-q-a/41480/multiperipheral-nus-crashes/161714#161714