To use serial console as main for kernel messages and init progress, change
console=tty1
to
console=ttyS0,115200
in boot script and recompile it using command at the end of the file.
Hello,
I am having a problem using the uart and I guess it is related with this topic.
I am trying to make my Hummingboard to communicate via UART with a serial ublox GPS. I identified that the right device in armbian (5.34) is /dev/ttymxc0 since it echoes characters when I join tx/rx together.
When I connect the GPS it starts sending gps data normally, but when I have to reboot the hummingboard, it does not boot.
I connected a screen to the HDMI interface to see what was happening, and I get the screen message as if a key had been pressed in order to stop booting process, so the boot stops here and the hummingboard does not come up. When I disconnect the GPS power or the UART, the HB boots normally, and the gpsd gets the serial port. when the gpsd is closed, agetty takes the control of the uart and I cannot use it again until I reboot.
I concluded that the boot was configured to take the console keyboard from the UART, so I modified /boot/boot.cmd as suggested in this thread; I found the line:
if test "${console}" = "serial" || test "${console}" = "both"; then setenv consoleargs "${consoleargs} console=ttymxc0,115200"; fi
So I changed to
if test "${console}" = "serial" || test "${console}" = "both"; then setenv consoleargs "console=tty1"; fi
in order to avoid the boot to grab the ttymxc0 serial port. I recompiled the boot.cmd and rebooted, but the problem persists. The boot is still stopped due to an abnormal keypress.
I have no idea of how to make it work, since I have tried the procedure above and also explored the alternative of resetting via hardware the GPS during hummingboard boot, but it still stops the booting. The GPS will be permanently connected to the hummingboard, so I cannot disconnect it everytime I reboot. Do you have any ideas about what would be the problem? How to avoid the boot to depend on the uart?
I also checked the boot configuration built on the kernel:
cat /boot/config-4.13.12-cubox |grep ttymxc
and th result was:
CONFIG_CMDLINE="noinitrd console=ttymxc0,115200"
Does this mean that I have to recompile the kernel to solve it?
Question
Gyver
Hello,
I am having a problem using the uart and I guess it is related with this topic.
I am trying to make my Hummingboard to communicate via UART with a serial ublox GPS. I identified that the right device in armbian (5.34) is /dev/ttymxc0 since it echoes characters when I join tx/rx together.
When I connect the GPS it starts sending gps data normally, but when I have to reboot the hummingboard, it does not boot.
I connected a screen to the HDMI interface to see what was happening, and I get the screen message as if a key had been pressed in order to stop booting process, so the boot stops here and the hummingboard does not come up. When I disconnect the GPS power or the UART, the HB boots normally, and the gpsd gets the serial port. when the gpsd is closed, agetty takes the control of the uart and I cannot use it again until I reboot.
I concluded that the boot was configured to take the console keyboard from the UART, so I modified /boot/boot.cmd as suggested in this thread; I found the line:
if test "${console}" = "serial" || test "${console}" = "both"; then setenv consoleargs "${consoleargs} console=ttymxc0,115200"; fi
So I changed to
if test "${console}" = "serial" || test "${console}" = "both"; then setenv consoleargs "console=tty1"; fi
in order to avoid the boot to grab the ttymxc0 serial port. I recompiled the boot.cmd and rebooted, but the problem persists. The boot is still stopped due to an abnormal keypress.
I have no idea of how to make it work, since I have tried the procedure above and also explored the alternative of resetting via hardware the GPS during hummingboard boot, but it still stops the booting. The GPS will be permanently connected to the hummingboard, so I cannot disconnect it everytime I reboot. Do you have any ideas about what would be the problem? How to avoid the boot to depend on the uart?
I also checked the boot configuration built on the kernel:
cat /boot/config-4.13.12-cubox |grep ttymxc
and th result was:
CONFIG_CMDLINE="noinitrd console=ttymxc0,115200"
Does this mean that I have to recompile the kernel to solve it?
Thanks very much in advance
Regards
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