# @Rishabh is this kind of usb-c port Channel: #designreview Source: https://discord.com/channels/1233487248129921135/1556049102335254610 Started: 2026-10-04T16:19:56.468000+00:00 Last activity: 2026-10-08T05:31:59.154000+00:00 ## shibo — 2026-10-03T21:03:35.991000+00:00 <@809856037376491570> is this kind of usb-c port viable? https://tscircuit.com/ShiboSoftwareDev/nema8-20mm-usbc-pd-controller Attachment: Screenshot_2026-10-03_at_11.02.29_PM.png — https://community.tscircuit.com/media/1556049101437542410 ## shibo — 2026-10-04T16:20:01.960000+00:00 <@809856037376491570> please review: https://tscircuit.com/ShiboSoftwareDev/nema8-20mm-dual-usbc-stepper-controller#3d ## Seve — 2026-10-04T16:20:45.184000+00:00 idk if i mentioned this last time but you need to be consistent w/ the usb ports and exit them all upward i think, otherwise it is difficult to integrate and looks weird ## Seve — 2026-10-04T16:20:48.678000+00:00 so they should all face up ## Seve — 2026-10-04T16:21:18.244000+00:00 then you should use the extra space to have four mounting holes ## shibo — 2026-10-05T08:23:30.101000+00:00 <@809856037376491570> https://tscircuit.com/ShiboSoftwareDev/nema8-20mm-dual-usbc-stepper-controller#3d ## Rishabh — 2026-10-05T09:03:21.041000+00:00 use standard schematics for usb Attachment: image.png — https://community.tscircuit.com/media/1556592620665577493 ## Rishabh — 2026-10-05T09:03:35.606000+00:00 I don't see silkscreen for PWR and DATA ## Rishabh — 2026-10-05T09:05:20.704000+00:00 make sure the current carrying wire is going through the outer layers ## Rishabh — 2026-10-05T09:07:08.089000+00:00 why such a big box? Attachment: image.png — https://community.tscircuit.com/media/1556593573909233684 ## shibo — 2026-10-05T12:29:42.714000+00:00 <@809856037376491570> please re review ## Rishabh — 2026-10-05T14:56:36.287000+00:00 I still see the usbc not using the standard schematic ## Rishabh — 2026-10-05T14:57:05.979000+00:00 You didn't change the power wires to outer layers ## Rishabh — 2026-10-05T14:57:16.346000+00:00 what should I re-review? ## shibo — 2026-10-05T16:00:08.662000+00:00 As the outer layers are cramped I moved the higher current routes and kept the lower current ones ## shibo — 2026-10-05T16:04:49.266000+00:00 I don't know what the standard schematic is, I tried to copy the one you had on one of your boards ## Seve — 2026-10-05T16:40:41.463000+00:00 forces the default schematic- there should be a warning and AI should be able to know how to correct it from the message but there's currently not ## shibo — 2026-10-06T04:25:07.306000+00:00 <@757706909351411845> can you please review? https://tscircuit.com/ShiboSoftwareDev/nema8-20mm-dual-usbc-stepper-controller#3d ## Seve — 2026-10-06T05:29:13.335000+00:00 where is the data mcu? ## shibo — 2026-10-06T11:00:31.331000+00:00 [attachment] Attachment: image.png — https://community.tscircuit.com/media/1556984495197130893 ## Seve — 2026-10-06T16:03:07.042000+00:00 that is a pd mcu iiuc ## shibo — 2026-10-06T16:07:49.072000+00:00 yeah, it’s a PD MCU, but it also supports USB data and can run the motor control firmware. it's called CH32X035 we use it for both jobs, so there isn’t a separate data MCU ## Seve — 2026-10-06T16:10:15.288000+00:00 ok so how are you controlling both USD PD and USB DATA with a single mcu? ## Seve — 2026-10-06T16:10:26.285000+00:00 (it's not possible) ## Seve — 2026-10-06T16:10:42.332000+00:00 also unless it has an adc you don't have current sense ## shibo — 2026-10-06T17:37:21.034000+00:00 the chip has separate hardware for USB data and USB-PD the driver chip senses and regulates motor current internally but the relevant signal is not connected to the MCU ## Seve — 2026-10-06T17:38:07.707000+00:00 Fake engineering ## Seve — 2026-10-06T17:38:16.279000+00:00 This board does not have usb pd ## Seve — 2026-10-06T17:40:09.241000+00:00 (Negotiating pd out of data does not count, of course, the whole point of data is to avoid PD) ## shibo — 2026-10-06T17:41:39.213000+00:00 we aren’t negotiating PD through the DATA port, PD negotiation happens on the separate PWR port through its CC pins ## Seve — 2026-10-06T17:43:41.581000+00:00 I think you are correct! ## Seve — 2026-10-06T17:44:06.385000+00:00 I was told DP and DM are required for PD by an eng and i did not question it ## Seve — 2026-10-06T17:44:38.226000+00:00 Do you have an adc with current sense ## Seve — 2026-10-06T17:45:12.237000+00:00 That is very clever <@778624824875941908> i have learned something important ## Seve — 2026-10-06T17:45:34.273000+00:00 You should also do the assembly ## shibo — 2026-10-06T17:45:34.829000+00:00 the driver chip senses current but i didn't connect the related signal to the mcu ## Seve — 2026-10-06T17:45:58.779000+00:00 Interesting ## Seve — 2026-10-06T17:46:12.427000+00:00 You are using the TMC driver, which is a very fancy driver ## Seve — 2026-10-06T17:46:16.417000+00:00 So it might be OK ## shibo — 2026-10-06T17:46:21.541000+00:00 wdym? adding the 3d model of the motor and connecting the board to it ## Seve — 2026-10-06T17:46:42.810000+00:00 Yeah, it’s good for verifying that everything is gonna fit together ## Seve — 2026-10-06T17:46:51.323000+00:00 Look up assembly.motor in the docs ## Seve — 2026-10-06T17:51:01.245000+00:00 Let’s have Rishabh review as well, but after that, I think we can probably order ## shibo — 2026-10-08T05:31:59.154000+00:00 <@809856037376491570> <@757706909351411845> the led would have to face upwards right? away from the motor