Enable serial console with dietpi-config should already do all steps for you, but to be sure:
Verify that /DietPi/config.txt contains the line enable_uart=1.
Verify that /DietPi/dietpi.txt contains the line CONFIG_SERIAL_CONSOLE_ENABLE=1.
NEVER do systemctl disable getty@tty1.service as TTY1 is always needed as fallback
Important when using UART devices for something else then a serial login console, is that you disable serial console usage. On DietPi do: dietpi-config > Advanced Options > Serial/UART
Hey, the regular ttyS0 works fine. The console usage is disabled via dietpi-config.
Verify that /DietPi/config.txt contains the line enable_uart=1.
Verify that /DietPi/dietpi.txt contains the line CONFIG_SERIAL_CONSOLE_ENABLE=1.
Directory DietPi does not exist anymore, this is now placed in boot directory. As mentioned enable_uart=1 is present in config.txt. CONFIG_SERIAL_CONSOLE_ENABLE=1 is also present in dietpi.txt.
Still the UART5 (AMA4) isn’t enabled. While the default ttySO works fine to connect with.
There is no other ttyS* device node which may represent UART5, is it? As we use the original RPi kernel and firmware, if the device tree overlay does not work, I is most likely a bug in the RPi kernel.
Sorry for replying this late, the only error the command shows you gave is:
root@DietPi:~# dmesg -l 0,1,2,3
[ 0.617813] bcm2708_fb soc:fb: Unable to determine number of FBs. Disabling driver.
I will run RPi OS to determine if it has same issue or not.
After running on RPI Os:
Result from command dmesg -l 0,1,2,3 is nothing. So no errors.
/boot/config.txt contains dtoverlay=uart5 below enable_uart=1.
Also when running dtoverlay -l in command prompt after reboot shows no active overlays loaded… (same as in dietpi).
Even when running sudo dtoverlay uart5 It will have it in the dtoverlay list(dtoverlay -l) until reboot is preformed it will say no active overlays found.
Serial connection ttyS0 works perfectly fine, same as dietpi.
Can a problem be the fact that multiple pins are connected, that one of these connections is the issue?
Or should i report this under RPI OS issues?
When running ls /dev/tty* a lot of different tty0, tty24, tty11, … only ttyAMA0 & ttyAMA1, no AMA4.