Arduino for STM32

Here you see the traces when polling a word from the VL53L1x. The yellow trace is the signal genersted with Timer 3. The purple is SCL on I2C. Clearly during the last part of the answer from the sensor Timer 3 goes into trouble.

https://www.dropbox.com/s/0xv1w77kpca5g ... 224550.jpg

Thank you for the replies! I am investigating the issue and will post code, but I need to simplify it before I can share. In the meantime I believe that I isolated the problem:

The issue is with the SparkFun_VL53L1X library, which relies on Wire. Specifically the VL53L1_RdWord function. When I ...

I need to regularly poll a sensor on I2C and to process samples + access a DAC on SPI, both operations are periodic, time critical and triggered by dedicated interrupts. I am using STM32Duino on Blue Pill and the Wire library for I2C.

My impression is that I2C reads are blocking, which introduces ...