How to deal with ETM Trace Overflows?

[Andrew]

I have been off and on trying to get ETM Trace working with the nRF52840 and Segger Ozone. It mostly works, but because the CPU clock runs at 64MHz and the Trace clock runs at 16MHz I experience Trace overflows as the nRF52840 creates trace data faster than it can send it out. Either the CPU clock needs to be reduced or the Trace clock needs to be increased in order to prevent this (32Mhz in either scenario). Of course, there is no way to do either of these things on the nRF52 series.

Is there any known way to configure the nRF52 and/or Trace setup to avoid trace overflows?

[Sigurd]

Hi,

You might want to have a look at these posts, they only focus on Keil though.

https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/debugging-nrf52-series-devices-using-trace

https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/nrf52-tutorial-etm-instruction-trace-with-keil-mdk

Is there any known way to configure the nRF52 and/or Trace setup to avoid trace overflows?

Fist make sure that TRACECONFIG is actually configured for max speed.

To prevent overflows you could try to disable timestamps, or set a timestamp prescaler. Also, not sure if it's possible with Ozone, but in Keil it seems to be possible to disable certain trace events you're not interested in.