Question: how are PMOD0/1 distinguished?

stone · November 11, 2021, 4:09am

Hi,

I have a question regarding PMOD 0/1 under base overlay, from the block diagram pmod0 and pmod1 are exactly same, and they also have exactly same mapped address for internal peripherals like i2c, spi, etc. However with python notebook we can distinguish between pmod0 and pmod1 when accessing the peripheral under it.

Does anyone know how are pmod0 and pmod1 are distinguished with the same address map?

Thanks.

marioruiz · November 11, 2021, 12:07pm

Hi @stone,

The IOP block contain a shared BRAM, and the offset address of this BRAM is how you identify each pmod block.

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

Furthermore, the base.py define these pmods like this.

github.com

Xilinx/PYNQ/blob/master/boards/Pynq-Z2/base/base.py#L88-L96


      
          self.iop_pmoda.mbtype = "Pmod"
          self.iop_pmodb.mbtype = "Pmod"
          self.iop_arduino.mbtype = "Arduino"
          self.iop_rpi.mbtype = "Rpi"
          
          
self.PMODA = self.iop_pmoda.mb_info
          self.PMODB = self.iop_pmodb.mb_info
          self.ARDUINO = self.iop_arduino.mb_info
          self.RPI = self.iop_rpi.mb_info

Mario

stone · November 11, 2021, 7:16pm

Got it. Thanks Mario

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Question: how are PMOD0/1 distinguished?

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