Convert OrangeCrab r0.2 ADC sense to diffpair #91
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.github/workflows/main.yml
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| @@ -8,6 +8,9 @@ jobs: | |||
| uses: actions/checkout@v2 | |||
| - name: Set up Python | |||
| uses: actions/setup-python@v2 | |||
| - name: Install nmigen | |||
| run: | | |||
| pip install git+https://github.com/nmigen/nmigen | |||
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Please drop this commit. I'm aware the CI is red, but the problem goes beyond CI to everyone who uses nmigen-boards, so it is a genuine issue with the repo rather than just a CI omission.
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I think you dropped the wrong one
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Oh, that commit wasn't supposed to be here. No clue how that happened, sorry.
nmigen_boards/orangecrab_r0_2.py
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| @@ -66,8 +66,7 @@ class OrangeCrabR0_2Platform(LatticeECP5Platform): | |||
| Resource("adc", 0, | |||
| Subsignal("ctrl", Pins("G1 F1", dir="o")), | |||
| Subsignal("mux", Pins("F4 F3 F2 H1", dir="o")), | |||
| Subsignal("sense_hi", Pins("H3", dir="i")), | |||
| Subsignal("sense_lo", Pins("G3", dir="i")), | |||
| Subsignal("sense", Pins("H3", dir="i"), Attrs(IO_TYPE="LVCMOS33D")) | |||
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Should the IO_TYPE be something different? In order for the ADC to work, sense_hi and sense_low need to be connected with a comparator
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Should be DiffPairs("H3", "G3", dir="i") at the very least. I have no special insight about IO_TYPE, that's up to the board designer mostly.
The OrangeCrab ADC utilizes the comparator in the ECP5 A/B pair to do level sensing. This requires "sense_hi"/"sense_lo" to be configured as a diff pair. Consolidate "sense_hi"/"sense_lo" into a diff pair "sense".