Date: Thu, 7 Feb 2019 19:21:30 +1100 From: Brian Scott <bscott@bunyatech.com.au> To: Dustin Marquess <dmarquess@gmail.com> Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: Serial Port on RPi3 Message-ID: <3d4c6514-14be-8443-85d3-255a11637f47@bunyatech.com.au> In-Reply-To: <CAJpsHY7trHxX2QDAnh--tE8UXnEAH0ZsQ2YZ2-Y0SppFYojPpA@mail.gmail.com> References: <75aa4f8f-1c93-0cc0-b3ed-0208c40098be@bunyatech.com.au> <CAJpsHY7trHxX2QDAnh--tE8UXnEAH0ZsQ2YZ2-Y0SppFYojPpA@mail.gmail.com>
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On 7/2/19 7:10 pm, Dustin Marquess wrote: > You're absolutely right about the PL011 speed change issue. I had the > same exact issue (for the exact same reason too, GPS!) and gonzo told > me to use init_uart_baud in my config.txt: > > https://lists.freebsd.org/pipermail/freebsd-arm/2017-January/015474.html > > I managed to get the older U-Boots to not spew on the UART at all. > The newer ones seem to desperately want one and panic/die/etc if they > can't find one. I spent hours on it and finally just gave up :(. > > -Dustin > > On Thu, Feb 7, 2019 at 12:17 AM Brian Scott <bscott@bunyatech.com.au> wrote: >> Hi, >> >> Has anyone had any success using the serial port on a Raspberry Pi 3 at >> anything other than 115200? >> >> I'm trying to connect a GPS module to it (as most people do...) but am >> having a lot of trouble. >> >> To give myself some diagnostics I have connected another machine up >> using an adafruit cable and a terminal program. >> >> My first problem was u-boot. I have largely managed to get it out of the >> way by setting the stdin, stdout and stderr environment variables to >> usbkbd, vidconsole, and vidconsole (i.e. removing the serial option) but >> it still insists on sending: >> >> MMC: mmc@7e300000: 1 >> Loading Environment from FAT... OK >> In: serial >> Out: vidconsole >> Err: vidconsole >> >> at 115200 baud before getting out of the way. No big deal because it >> doesn't look like gps commands and it is being sent at much higher >> speeds than I would expect the gps to understand anyway. >> >> The message on boot for the UART is: >> >> uart0: <PrimeCell UART (PL011)> mem 0x7e201000-0x7e201fff irq 24 on >> simplebus0 >> >> If I send data to the uart (echo Hi >/dev/cuau0) it works but at 115200 >> baud, not respecting the stty speed of 9600. Similarly, using cu (cu -l >> cuau0 -s 9600), I can send data but at 115200, not the expected 9600 baud. >> >> I have done some experiments with enable_uart= in the config.txt as well >> as overlays from the linux world (uart0.dtbo and uart1.dtbo). While I >> can get FreeBSD to detect the Mini-UART with some combinations of >> settings, either on it's own or with the PL011, I haven't been able to >> get anything out of the mini-uart and only a single character out of the >> PL011 (at 115200 baud despite other settings). >> >> My conclusions so far: >> >> * There is no working driver behind the detection of the mini-uart. >> * There is no way to change the speed of the PL011 to anything other >> than 115200 (maybe because u-boot sets it that way at startup - >> haven't fiddled with those knobs yet). >> >> Am I missing something important somewhere? >> >> Cheers, >> >> Brian >> >> P.S. I'm running 12-RELEASE with no software changes. >> >> >> _______________________________________________ >> freebsd-arm@freebsd.org mailing list >> https://lists.freebsd.org/mailman/listinfo/freebsd-arm >> To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org" Thanks. Just the magic I'm looking for. Cheers Brian
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