Measuring MOCO and SOSC without GPT or CLKOUT

Hello,

I try to find a reliable and reproducable method to measure the MOCO and SOSC for S3A1 and S3A6. Sadly I can't use the CLKOUT feature or a PWM out via GTIOCA or GTIOCB.

Is there a realiable way over GPIO toggling?

kind regards

Benjamin