Why Pmod_ADC can't log more than 1007 data?

Hi all,

I want to use PYNQ-Z2 to record a signal, and the tutorial taught me to use Pmod AD2 to convert analog signal to digital.
pmod adc example

However, using the Pmod_ADC lib, I can’t log more than 1007 data, as shown.

By varying the sleep time from 1s to 0.2s, the length of data stayed at most 1007, and became 731 when sleep 0.1s.

Could anyone please tell me why?

Hi @splx,

The shared memory of the MicroBlaze subsystem is 64KB. Hence, there is a limit of the number of samples you can store.

https://pynq.readthedocs.io/en/latest/overlay_design_methodology/pynq_microblaze_subsystem.html#pynq-microblaze-memory-map

If you want to be able to store more samples you will have to increase this memory and rebuild the bitstream and corresponding bsp.

Mario

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