I have updated beaglebon black emmc with “Debian GNU/Linux 12 (bookworm)”
I want to use UART4, Can you guide me with this?
I first want to check it in loopback mode.
Hey There,
I have used Bookworm before today. I am not sure about the eMMC fitting Bookworm on it but…
ls -l /dev/bone/uart/* will report things to your output. The output may be a sign of if you need to add an overlay or not.
What does ls -l /dev/bone/uart/* output?
Also, if you need to put an overlay in /boot/uEnv.txt, you can under the listed overlays section(s).
There may be overlays in various files and looking through them will prove valuable.
lrwxrwxrwx 1 root root 11 Dec 26 19:58 0 → ../../ttyS0
lrwxrwxrwx 1 root root 11 Dec 26 19:58 1 → ../../ttyS1
lrwxrwxrwx 1 root root 11 Dec 26 19:58 2 → ../../ttyS2
lrwxrwxrwx 1 root root 11 Dec 26 19:58 3 → ../../ttyS3
lrwxrwxrwx 1 root root 11 Dec 26 19:58 5 → ../../ttyS5
need to add “BB-UART4-00A0.dtbo” to uEnv.txt and reboot
uboot_overlay_addr4=BB-UART4-00A0.dtbo
lrwxrwxrwx 1 root root 11 Dec 26 20:43 0 → ../../ttyS0
lrwxrwxrwx 1 root root 11 Dec 26 20:43 1 → ../../ttyS1
lrwxrwxrwx 1 root root 11 Dec 26 20:43 2 → ../../ttyS2
lrwxrwxrwx 1 root root 11 Dec 26 20:43 3 → ../../ttyS3
lrwxrwxrwx 1 root root 11 Dec 26 20:43 4 → ../../ttyS4
lrwxrwxrwx 1 root root 11 Dec 26 20:43 5 → ../../ttyS5
Debian Bullseye IoT Image 2023-10-07
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Thank you, This helped
Now i have an LCD display (7 inch TFT 800x480 24 bit parallel RGB) connected to P8_27 to P8_46) How to enable this?
Currently i have connected display at HDMI but for my application I will use this mentioned LCD.
that has a lot of unknowns,
so i have a 4d cape 7” with resistive touch, it uses a dts of 4dcape70t something.
i would have to assume that the display you are using has an associated dts/dtsi. within in that file is where you would need to make your changes. without knowing the detail, it’s like throwing darts in the dark. 
one other issue: seems these are hardwire to the hdmi, not sure you can just change them
debian@BeagleBone:~$ gpioinfo | grep P8_27
line 22: “P8_27 [hdmi]” “P8_27” input active-high [used]
debian@BeagleBone:~$ gpioinfo | grep P8_46
line 7: “P8_46 [hdmi]” “P8_46” input active-high [used]
might want to open a new issue, being this thread has been marked as solved.