Hi @weasel79, glad you found the code useful.
Personally I sadly haven't used the max11300 for anything useful yet, too many projects, too little time, but maybe now is the time to pick it up again, thanks for the reminder.
It was a while ago I did this, and the code was borrowed from other people, from an arduino script originally, so I really don't remember every detail, but I poked around in the axoloti-object and found there is a 1 millisecond delay in the looping code that may explain the 800 Hz. I don't remember if I tested without the delay or if I just put it there because there was a similar delay in the arduino code, and I thought it was needed.
The while-loop calls the "loop()" function, witch is inherited from arduino, where it loops, but here, in axoloti, it needs to be called repeatedly to loop. (I don't remember if I wrote his or if I borrowed it from someone, it was three years ago).
After the call to "loop()" there is a "chThdSleepMilliseconds(1)". Comment out that line and see what happens, I can't try it myself since I'm away on holiday and my axoloti's back home.
Let me know if it works