Then I tried to enable UART-AO-B on the GPIOAO 8 & GPIOAO 9, so I modified the file /boot/eEnv.txt with “overlays=meson-g12a-uart-ao-b-gpioao-8-gpioao-9”, rebooted the system I ran the command “dmesg | grep tty”. I do not see any changes to list
gave it another try but the second time was with “overlays=meson-g12a-uart-ao-b-on-gpioao-8-gpioao-9”. I still do not see any change when I run "dmesg | grep tty"
am I missing something, have typo or are the UARTs are enabled by default? if yes how do I view it in the terminal
Hi hishi, not sure the thing you would do with the UART_AO_A as I do, but I made some progress, and probably that can help you.
I want to use the radxa zero with my Prusa i3MK3s, which seems to be a good fit as the GPIO pin head definition is the same as raspberry pi zero, see this post.
For this application, I just want only python to access the /dev/ttyAML0 after the software octoprint starts. The problem is that because the kernel is also using this resource, thus python will throw an error, also the UART won’t work with communicating with Prusa. What I did is that I follow the documentation, turn on the /dev/ttyAML1, and I modify the console configuration from /dev/ttyAML0 to /dev/ttyAML1 in /boot/uEnv.txt, thus no one is using /dev/ttyAML0 after the system starts running the operating system, so python can use it happily.
I haven’t connected it with my Prusa, probably I will try it tomorrow, but it seems to be fine to run python3 -m serial.tools.miniterm /dev/ttyAML0 115200 with my USB serial, which does not work before for python will throw an error saying that other program is also using this resource.
Hi Stephen, can I just update the kernel and set overlays=meson-g12a-uart-ao-a-on-gpioao-0-gpioao-1 to use UART_AO_A from release radxa-zero-v20211010?
Oh, I did not install the latest image, just I saw the line:
Serial console
To set UART_AO_A as serial console, add the following two lines to /boot/uEnv.txt
console=ttyAML0,115200
overlays=meson-g12a-uart-ao-a-on-gpioao-0-gpioao-1
, so I thought the console setting is removed, and no console is available. My bad if the serial console still works with the latest release by default, I did not give it a test but just guessed.
Hi, I cannot get the UART_AO_B serial port appearing in /dev with the latest image radxa-zero-ubuntu-focal-server-arm64-20220801-0346-mbr.img. Actually, even the default console at UART_AO_A does not seem to work.
The dmesg shows the following (among other):
$ dmesg|grep tty
[ 0.000000] Kernel command line: earlyprintk console=ttyAML0,115200 console=tty1 rw rootfstype=ext4 init=/sbin/init rootwait swiotlb=1 coherent_pool=1m root=UUID=a1d6d1b5-7219-4126-8ecd-e5cf6265cfc6
[ 0.000574] printk: console [tty1] enabled
[ 1.542482] ffd24000.serial: ttyAML2 at MMIO 0xffd24000 (irq = 26, base_baud = 1500000) is a meson_uart
[ 1.542691] serial serial0: tty port ttyAML2 registered
No support from Radxa - another day spent on the device: I noticed the uEnv.txt has no effect on booting whatsoever. Inspecting the booting process from the serial console more properly finally showed why: the file extlinux/extlinux.conf is found and loaded by the bootloader instead. Removing this file solves both problems: failed booting (due to the wrong path to the DTB) and no serial ports working (due to overlays not loaded at all).
After removing extlinux/extlinux.conf from the boot partition, the boot.scr is correctly loaded instead, and the uEnv.txt is finally applied.
Am I the only person using the Radxa Zero with the new and broken images? Is nobody even testing the images?
Yeah, that is the other possibility. But all the current documentation only mentions the uEnv.txt and in the other thread you mention that extlinux.conf does not support overlay parameters (not that I would currently use them, but maybe I will want to later).
So, I consider it strange that this file (with a preference!) is present and (in addition) it includes a typo preventing the system to even boot at all.
