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#sky130
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# sky130
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Tobias Strauch

01/20/2022, 8:27 PM
Hi @User, nice meeting you at ORConf17 in Hebden Bridge. I was the bad guy asking “What about DFT ...” in the Q&A section. Still feeling sorry for that. I see that there are some activities in the sky130\DFT ongoing. I did some research in the DFT field [1] years back and I was wondering, if it is possible to design a custom Scan-DFF (basically with a second mux and one more in- and one more output). I took a layout course 25 years back, so I could eventually design it, but would it be possible to manufacture it with MPW-N ? It would be one of these dream-comes-true moments. Thank you for your answer in advance. Cheers, Tobias [1] https://ieeexplore.ieee.org/document/5753986
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Tim Edwards

01/20/2022, 9:06 PM
"What about DFT" was a perfectly valid question. : ) And it has taken much longer to get around to implementing it than I had expected. I'm not sure exactly what you're doing with the multiple-mux, multiple-input cell design (I don't have access to IEEE Explore), but sure, it can be done on an MPW run. You can use the SkyWater standard cell set like
sky130_fd_sc_hd
, start with one of their basic scan flops, and redesign it as you see fit. I have done a few custom variations on the PDK cells. It's easy enough if you stick with multiples of the unit cell width and maintain the various implant layers that stretch the width of the standard cell. If you plan to start with a small test circuit, as opposed to creating a DFT-supported microcontroller, you might want to check with Matt Venn about his "multi-multi project", where he synthesizes around a dozen small projects into one MPW submission. But regardless, it sounds like a perfect project for a SkyWater MPW run.
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Matt Venn

01/21/2022, 10:00 AM
👋
We had a custom cell in our last run so it's definitely doable
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Tobias Strauch

01/21/2022, 11:29 AM
Thank you for your reply. I have the feeling, that slack is going to be my best friend in the upcoming months...
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Matt Venn

01/21/2022, 1:26 PM
Make sure you copy important info
Messages last for a few months