On Fri, Jun 04, 2021 at 04:16:26PM -0700, David Frey wrote: > I'm not sure if this matters, but I have been told that the failing > boards have CP2102N chips with"A01" firmware. I tried to install > SIlicon Labs Simplicity Studio on Windows because I read that it would > be able to identify the firmware version of the device, but I couldn't > actually figure out how to find the information. If someone can tell > me a way to get the firmware version, I can check to see if it's > different between the device that does exhibit this failure and the > one that doesn't. That is definitely worth pursuing. The A01 is apparently EOLed and there's a later A02 and possibly even A03: https://www.silabs.com/community/interface/knowledge-base.entry.html/2020/03/31/how_to_determinecp2102nrevisiona01vsa02-DCJI That page refers to that vendor tool "Simplicity Studio" as well as a Windows library described by https://www.silabs.com/documents/public/application-notes/AN978-cp210x-usb-to-uart-api-specification.pdf that can be used to read out the firmware version on CP2102N and CP2108 (three bytes). We just need to figure out which vendor request the library (and tool) uses and we could key off of this in the driver if this turns out to be related to the firmware revision. If anyone's got a Windows installation it may be possible to dump the USB traffic using Wireshark to determine the request. Unless Silabs can chime in here of course. I found an errata for A01 on here, but no mention if this particular bug: https://www.silabs.com/documents/public/pcns/190315471-CP2102N-Product-Revision-with-Datasheet-and-Errata-Update.pdf > On Fri, Jun 4, 2021 at 8:42 AM Johan Hovold <johan@xxxxxxxxxx> wrote: > > This all matches the CP2102N I've got here and which can set RTS just > > fine also with the IXOFF limits set (unlike your device). > > > > Unless there's some other configuration setting causing it would seem > > your device firmware is just buggy (and bcdDevice was not updated when > > it was fixed, which seems unlikely). Johan
