So I finally got it working for the assembly-like ulp-code. The key was as You said the custom function without the return-instructions except of ESP_OK and changing the LENGTH-value in esp32.ulp.ld: ram(RW) : ORIGIN = 0, LENGTH = 8192. A #define here will not work. I have to test it more to say mor...

I'm actually don't using the macros but the "real" ulp instruction instead. Unfortunatly I couldn't get it working for me with the function ulp_load_binary in ulp.c . When I try to upload an ulp-program with more than 512 bytes.

Anyway, if you want a workaround you can either copy the function into your code, or just edit the function to skip the size check for now. It will load and run fine, it will just overflow into RTC slow memory so you'll need to manually write and read from the actual offset if you're using it (eg. ...

So did it work for You in the end?
If it worked, what did You change exactly?
I ran into the same problem of less space then specified.
I measured just as You that 500 bytes of pure commands is the limit.
https://github.com/duff2013/arduino_ulp/issues/21

I wanted to use an MPU6050 accelerometer with the ulp-coprocessor. I have set the registers according to the technical reference https://www.espressif.com/sites/default/files/documentation/esp32_technical_reference_manual_en.pdf#183 but I can't communicate with it. Here's my code: .text .global entr...