# Question: how are PMOD0/1 distinguished?

**URL:** <https://discuss.pynq.io/t/question-how-are-pmod0-1-distinguished/3287>\
**Category:** Support\
**Created:** [November 11, 2021, 4:09am UTC](https://discuss.pynq.io/t/question-how-are-pmod0-1-distinguished/3287 "2021-11-11T04:09:07Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![stone](https://avatars.discourse-cdn.com/v4/letter/s/c89c15/32.png) [@stone](https://discuss.pynq.io/u/stone)\
**Post date:** [November 11, 2021, 4:09am UTC](https://discuss.pynq.io/t/question-how-are-pmod0-1-distinguished/3287/1 "2021-11-11T04:09:08Z")

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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.

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**Author:** ![marioruiz](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/marioruiz/32/2177_2.png) [@marioruiz](https://discuss.pynq.io/u/marioruiz)\
**Post date:** [November 11, 2021, 12:07pm UTC](https://discuss.pynq.io/t/question-how-are-pmod0-1-distinguished/3287/2 "2021-11-11T12:07:23Z")

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

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

> <https://github.com/Xilinx/PYNQ/blob/master/boards/Pynq-Z2/base/base.py#L88-L96>

Mario

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<div class="post-metadata">

**Author:** ![stone](https://avatars.discourse-cdn.com/v4/letter/s/c89c15/32.png) [@stone](https://discuss.pynq.io/u/stone)\
**Post date:** [November 11, 2021, 7:16pm UTC](https://discuss.pynq.io/t/question-how-are-pmod0-1-distinguished/3287/3 "2021-11-11T19:16:55Z")

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Got it. Thanks Mario