Hello, I am using ETM on ARM Cortex M4 on NUCLEOF411RE and I would like to access its registers from software application. The problem is that I am not able to control ETM registers. More details below.

 I am following this procedure:

- set the lock access register for software access, by writing on it the value of 0xC5ACCE55.

- set the programming bit in ETM control register

- check whether the programming bit is set or not in ETM status register.

The problem is that I am not able to change the programming bit. I am using a read-modify-write procedure to do this.

I think that something is keeping my ARM Cortex M4 ETM stuck at their reset values.

Anyone worked with this issues or, in general, with software access to ETM?