Date: Sat, 21 Jan 2023 19:34:59 -0700 From: John Rushford <jjrushford@gmail.com> To: "freebsd-arm@freebsd.org" <freebsd-arm@FreeBSD.org> Subject: Pi 4 uarts Message-ID: <6496EB45-1CC8-4BF3-8A5E-A90039485D2F@gmail.com>
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Greetings, I have installed FreeBSD 13.1 on a raspberry PI 4b rev 1.4 and I am = trying to use the additional serial ports that are available with the PI = 4 with an Adafruit ultimate GPS card. I found that it was problematic using the first serial port ttyu0 on = GPIO pins 14 and 15 as data on the line from the GPS would interrupt the = boot process and I verified that I was in fact able see data time stamps = from the GPS card on the first uart port once I got FreeBSD to boot. Now since I do not wish to use the first serial port, I=E2=80=99ve built = the rpi-firmware port and copied all the uart dtb=E2=80=99s to = /boot/msdos/overlays and I=E2=80=99ve tried enabling the uart=E2=80=99s = in /boot/msdos/config.txt with =E2=80=9Cdtoverlay=3Duart3=E2=80=9D for = example. =20 Enabling them does in fact result in device entries created for them in = /dev but, I am unable to see any data on the corresponding ttyuX or = cuauX ports. Just to eliminate a wiring error, I installed another SD card with = Raspberry PI OS, enabled uart3 and I am able to see data on uart3 = without any issue confirming I have everything wired up properly. With FreeBSD, I have set the proper baud rate on the ports and I=E2=80=99v= e tried disabling flow control on them, using stty, but no matter what I = do, I never see any data on them. Unless I=E2=80=99m missing something, = I can only conclude there is some bug in FreeBSD preventing me from = using these additional serial ports. Has anyone here on this mailing = list been able to use them? If so, what does it take? thanks John jjrushford@gmail.com
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