Looking at the post from Google GMail, it does not specify what board the post is from. It just says Beagle Board.
Are you trying to connect directly to the PB via serial or are you using something like a FTDI interface to communicate to via serial? Assuming you are using some sort of Linux host, if you type 'dmesg' it should tell you what tty device enumerated for the interface. Also, have you set the 'udev' entries on your host for the BeagleBoard device? Ex See the "mkudevrule.sh" script from the following link: https://beagleboard.org/getting-started Jon On Sun, Dec 20, 2020 at 2:15 PM Robert Berger <[email protected]> wrote: > Hi, > > My comments are in-line. > > On 20/12/2020 22:54, Dennis Lee Bieber wrote: > > On Sat, 19 Dec 2020 02:16:56 -0800 (PST), in > > gmane.comp.hardware.beagleboard.user "robert.berger" > > <[email protected]> wrote: > > > > There is a distinct lack of information in this post. > > > >> Hi, > >> > >> I tried in a couple of ways to get something out of the serial console > >> while booting (U-Boot, kernel, console,..) > >> > > Which Beagle are you using? > > Pocketbeagle > > I posted it under "pocketbeagle" and thought that would be more obvious, > but it does not seem to be. > > > > >> This seems extremely unstable and random. > > > > What results have you obtained that cause you to make that > statement. > > screen /dev/ttyUSB4 115200 > > From "nothing" to some gibberisch (non ASCII characters, sometimes some > ASCII characters) > > after the board is booted screen /dev/ttyACM0 115200 works fine, but > that's NOT what I want. > > > Presuming you are wired properly to the board, > > That could be one problem, I guess, hence I am searching for a device > which might work, as already indicated in another reply and the docs[3][4] > > [3] https://shop.mikroe.com/ftdi-click > [4] > > https://www.ftdichip.com/Support/Documents/DataSheets/Cables/DS_TTL-232R_RPi.pdf > > I wired > > Board Adapter > > Txd Rxd > Rxd Txd > GND GND > > For the RS232 solution I also added 3.3V. > > I don't dare to switch from 3.3 to 5V, since this could cause damage. > > > and configured the USB side > > for the serial bit rate*, anything the board sends on the UART should be > > available via the virtual serial port on the USB side. > > Not really everything the board sends. Out of the box only stuff from > the time the "virtual" serial port starts. > > I see the "virtual" serial port, but I would like to see the "console" > output starting from the first line of MLO. > > debian@beaglebone:~$ cat /proc/cmdline > console=ttyO0,115200n8 root=/dev/mmcblk0p1 ro rootfstype=ext4 rootwait > coherent_pool=1M net.ifnames=0 lpj=1990656 rng_core.default_quality=100 > quiet > > I am also a bit confused about the ttyO0, although there is also a ttyS0;) > > So I am not sure which one is supposed to be the "real" serial. > > > > >> > >> One device I tried is this[1] with 3.3V. > >> > >> Another device is this[2]. > >> > >> Can you please advise which serial adapter to use? > >> > > > > Given how most computers have been dropping RS-232 connections, #2 > > seems to be an exercise in futility -- You have a 3.3V TTL UART being > > converted to full 9-pin RS-232, only to then need an RS-232 to USB > adapter > > to connect to modern computers. > > Not really. > > 1) Quite a few boards have TTL or real RS-232 outputs. So why go to USB > and not directly to good old RS-232? > > 2) I have a board farm and console servers with RS-232 connectors (RJ45 > connectors with RS232 signals), which would be my preferred solution. > > Unfortunately some newer boards only have USB connectors. Those I > connect via USB cables to USB hubs. But in any case I would like to see > the complete boot log (from MLO) and not just when the kernel is available. > > > > > > > > > * The USB protocol itself does not care about bit-rate -- it works > in USB > > speed packets. However, the chip-set on the adapter needs to be told what > > bit-rate the far end is sending... > > > > > > Regards, > > Robert > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/ec68fc45-ed93-3bbc-bb0f-c8135531283f%40gmail.com > . > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAG99bko4GrCfWn78BySwK64XBBtaeqdLGs7LkHS4WG_Ky%2B0Ctw%40mail.gmail.com.
