5 ms·
> This one "sniffs" the link just for the Power Delivery negotiations that happen at the lowest electrical levels. If a device or cable is misbehaving, a knowle
by normie3000 2y ago
> This one "sniffs" the link just for the Power Delivery negotiations that happen at the lowest electrical levels. If a device or cable is misbehaving, a knowledgeable person should be able to replicate the problem and see it happening with the sniffer. They could see which component was not following spec, and most importantly, exactly what it was doing wrong.
>
> Even if your computer is participating in Power Delivery, it can't see its own PD traffic because all that is handled at a low level by ASIC chips in your USB port. Hence the need for a separate physical device to see the signals that are actually being sent on the wire.
https://www.reddit.com/r/UsbCHardware/comments/qmz9uz/twonkie_homeassembled_googleinspired_usbpd/ https://www.reddit.com/r/UsbCHardware/comments/qmz9uz/twonki...
- transpute 2y agoEquivalent commercial PD analyer is ~$200, https://www.infineon.com/cms/en/product/evaluation-boards/cy4500/ https://www.infineon.com/cms/en/product/evaluation-boards/cy... > records traffic passively on the Configuration Channel (CC) and allows users to analyze and debug USB Power Delivery communication.. acts as a pass-through for VBUS, VCONN, USB 3.1, USB 2.0 and USB-PD traffic Total Phase / Google Twinkie device with Sigrok Pulseview software, https://www.totalphase.com/blog/2015/10/usb-power-delivery-analyzer-summary-resources-2/ https://www.totalphase.com/blog/2015/10/usb-power-delivery-a...
- deleted 2y ago[deleted]
- nimish 2y agoMore like $60, or charger lab has a nicer one for about the same price. https://estore.st.com/en/products/evaluation-tools/product-evaluation-tools/mcu-mpu-eval-tools/stm32-mcu-mpu-eval-tools/stm32-discovery-kits/stm32g071b-disco.html https://estore.st.com/en/products/evaluation-tools/product-e...
- Panzer04 2y agoNicer in what way? I've used the one referenced in the first comment (CY4500) and it worked quite well. I'm not entirely sure what could be done better. Nice to know that cheaper ones exist though - is the supporting SW any good (reading out packets, recording etc)
- nimish 2y agoNicer in that it has a good HMI. Anandtech has a nice review: https://www.anandtech.com/show/18944/usbc-power-metering-with-the-chargerlab-km003c-a-google-twinkie-alternative https://www.anandtech.com/show/18944/usbc-power-metering-wit...
- Panzer04 2y agoThis isn't quite the same thing, I think. The Cypress one has decent software for reading individual PD packets and debugging PD/TCPM implementations. Even if you can read out the packets with that, it doesn't look like it has a good pre-existing analysis software for it, which is a large part of the value proposition for the cypress version.
- nimish 2y agoThat's what sigrok or wireshark are for, IMO. Of course, you lose something for half the price. The ST one does have a protocol analyzer.
- Panzer04 2y agoWell, you can't read PD packets at that layer - they are only realistically visible at the driver layer and below, as the TCPM driver will manage the PD negotiation (and the main benefit of these analysers, at least for me, was to help write such a driver in the first place :))
- transpute 2y ago> charger lab has a nicer one Power-Z KM003C? https://www.amazon.com/ChargerLAB-KM003C-Portable-Charging-Voltmeter/dp/B0BJ24PVNJ/ https://www.amazon.com/ChargerLAB-KM003C-Portable-Charging-V...