On Mon, Dec 12, 2016 at 7:54 AM, Johan Hovold <johan@xxxxxxxxxx> wrote: > On Mon, Dec 12, 2016 at 07:51:59AM -0800, Russell Senior wrote: >> On Mon, Dec 12, 2016 at 7:40 AM, Johan Hovold <johan@xxxxxxxxxx> wrote: >> > On Mon, Dec 12, 2016 at 07:09:34AM -0800, Russell Senior wrote: >> >> On Mon, Dec 12, 2016 at 1:54 AM, Johan Hovold <johan@xxxxxxxxxx> wrote: >> >> >> >> > Ok, so maybe your device simply does not support changing the line >> >> > settings more than once. That is, the initial settings chosen are used >> >> > until re-connected. This would seem to be in accordance with a comment >> >> > found in one of the out-of-tree drivers floating around (and which at >> >> > least I hoped would no longer be an issue with the new way of changing >> >> > the settings). >> >> > >> >> > If you connect the ch340 you have in loopback mode, with the removed >> >> > initial LCR write that fixed the 5-bit behaviour, can you get that >> >> > behaviour back by setting 5-bit word size after opening the port? (This >> >> > was what I was going for with my original question above.). >> >> >> >> With minicom configured with 5N1 (that is, 5-bit mode), loopback looks >> >> normal. I type an 'a' and I get and 'a' back. Likewise, I type an >> >> 'A' and I get an 'A' back. I used a saved .minicom.dfl file to >> >> configure the port. >> > >> > Ok, so that seems to confirm the suspicion that changing settings after >> > the initial configuration is failing (even though the device does indeed >> > support 5-bit mode). >> > >> > Could you try to verify if that applies to the baud rate as well? That >> > is, can you switch between say 9600 and 115200 after opening the port >> > and verify that against the pl2303? >> > >> > Still using usb-linus with the first LCR write removed. >> >> I can change the baud rate on the ch341 and make it not work with the >> pl2303 (e.g. I send an 'A' from the pl2030 and get an 0xff on the >> ch341, and vice versa), then harmonize the baud rate again and it >> works again. Changing baud rate seems to work. > > That's good. And just to confirm: you managed to get characters through > at both rates? Yes, indeed. When the baud rates match (tested 9600 and 115200), characters arrive as expected in both directions. For what it's worth, changing byte-size to 5-bits on the pl2303 and sending data from it results in gibberish arriving on the ch341, implying that the pl2303 is changing byte size. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
