I managed to get the kind of echo effect I wanted by shifting to code blocks. Now, I write mix (signal + echo) to SRAM. The result is that echo will repeat several times.
Now I’m facing a new problem
The echos repeated get quite/weaker from time to time. So that an initial input is fading out over five repetitions. I failed in finding out where this is happening.
My guess here:
echo = echo >> 1; // attenuate echo
Is there a way to reduce the level by eg. 5%?