Hi.
UART-1, UART-5 has been activated through overlays operation.
edited /boot/firmware/extlinux/extlinux.conf
“fdtoverlays /overlays/BONE-UART1.dtbo /overlays/BONE-UART5dtbo”
UBOOT: Booted Device-Tree:[k3-j721e-beagleboneai64.dts]
UBOOT: Loaded Overlay:[BBAI64-CSI0-imx219.kernel]
UBOOT: Loaded Overlay:[BONE-I2C1.kernel]
UBOOT: Loaded Overlay:[BONE-UART1.kernel]
UBOOT: Loaded Overlay:[BONE-UART5.kernel]
kernel:[5.10.153-ti-arm64-r84]
debian@BeagleBone:~$ ls /dev/bone/uart
0 1 5
I want to use five UART Serials and don’t know what to do to use more UART serial.
Hi @ALEX_PARK those were just the first uart’s i got physically working… I need to go back thru the list now that more of the peripheral clock and power have been enabled on the core.
Regards,
2 Likes
Thankyou @RobertCNelson. Successed five UART open.
‘k3-j721e-beagleboneai64.dts’ was modified and succeeded.
1 Like
Do you know where I can get a copy of the overlays? I did a git pull to my /opt/source/dtb-5.10-ti and it is up to date. I have only one UART overlay and it is for UART1. Also what other changes are required.
$ sudo beagle-version | grep UBOOT
UBOOT: Booted Device-Tree:[k3-j721e-beagleboneai64.dts]
UBOOT: Loaded Overlay:[BONE-PWM0.kernel]
UBOOT: Loaded Overlay:[BONE-PWM1.kernel]
UBOOT: Loaded Overlay:[BONE-PWM2.kernel]
I tried to add the BONE-UART1.dtbo to the extlinux.conf. I then copied the BONE-UART1.dtbo to the /boot/dtbs/5.10.153-ti-arm64-r86.ti.overlays folder. The reboot failed, so I removed the line in the extlinux.conf that I just added for BONE-UART1.dtbo. I have noticed that their is no fragment for main_uart1 or main_uart2, in the k3-j721e-beagleboardai64.dts. Also uart3, uart6, uart7, uart8, and uart9 have status=“disabled”.
$ cat /opt/source/dtb-5.10-ti/src/arm64/k3-j721e-beagleboneai64.dts
main_uart0_pins_default: main-uart0-pins-default {
&wkup_uart0 {
&main_uart0 {
pinctrl-0 = <&main_uart0_pins_default>;
&main_uart3 {
&main_uart6 {
&main_uart7 {
&main_uart8 {
&main_uart9 {
BONE-UART1 on the expansion header is $main_uart2 on bbai64 soc. Beagleboard:BeagleBone cape interface spec - eLinux.org
Regards,
I actived five uart port.
I modified ‘k3-j721e-beagleboneai64-bone-buses.dtsi’
bone_uart_3: &main_uart3 {
/* tested /
pinctrl-names = “default”;
pinctrl-0 = <
&P9_17_uart_pin / uart3_txd /
&P9_12_uart_pin / uart3_rxd */
;
symlink = “bone/uart/3”;
status = “okay”;
};
A similar correction would do.
I referred to the pin map [Connectors — BeagleBoard Documentation]
/home/pops/opt/source/dtb-5.10-ti/src/arm64/k3-j721e-beagleboneai64.dts did you change:
from:
&main_uart3 {
/* UART not brought out /
status = “disabled”;
};
to:
&main_uart3 {
/ UART not brought out */
status = “okay”;
};
Having trouble getting enough UARTS. I was successfull getting UART1 functioning. So I tried to get UART5 to function by modifying “k3-j721e-beagleboneai64-bone-buses.dtsi” as follows:
bone_uart_5: &main_uart5 {
pinctrl-names = “default”;
pinctrl-0 = <
&P8_37_uart_pin /* uart2_txd /
&P8_38_uart_pin / uart2_rxd */
>;
symlink = “bone/uart/5”;
status = “disabled”;
};
Then created an overlay by modifying “BONE-UART1.dts” as follows:
// SPDX-License-Identifier: GPL-2.0
/*
/dts-v1/;
/plugin/;
/*
- Helper to show loaded overlays under: /proc/device-tree/chosen/overlays/
*/
&{/chosen} {
overlays {
BONE-UART5.kernel = TIMESTAMP;
};
};
&bone_uart_5 {
status = “okay”;
};
Then recompiled source files followed by a " make install_arm64" and added the overlay to the “extlinux.conf” file.
model:[BeagleBoard.org_BeagleBone_AI-64]
dogtag:[BeagleBoard.org Debian Bullseye Xfce Image 2023-02-05]
bootloader:[/dev/mmcblk0boot0]:[tiboot3.bin]:[U-Boot SPL 2021.01-gc21ddbdf (Nov 28 2022 - 15:42:44 +0000)]
bootloader:[/dev/mmcblk0]:[/boot/firmware/tiboot3.bin]:[U-Boot SPL 2021.01-gc21ddbdf (Nov 28 2022 - 15:42:44 +0000)]
bootloader:[/dev/mmcblk0]:[/boot/firmware/tispl.bin]:[U-Boot SPL 2021.01-gc21ddbdf (Nov 28 2022 - 15:42:44 +0000)]
bootloader:[/dev/mmcblk0]:[/boot/firmware/u-boot.img]:[U-Boot 2021.01-gc21ddbdf (Nov 28 2022 - 15:42:44 +0000)]
bootloader:[/dev/mmcblk1]:[/boot/firmware/tiboot3.bin]:[U-Boot SPL 2021.01-gc21ddbdf (Nov 28 2022 - 15:42:44 +0000)]
bootloader:[/dev/mmcblk1]:[/boot/firmware/tispl.bin]:[U-Boot SPL 2021.01-gc21ddbdf (Nov 28 2022 - 15:42:44 +0000)]
bootloader:[/dev/mmcblk1]:[/boot/firmware/u-boot.img]:[U-Boot 2021.01-gc21ddbdf (Nov 28 2022 - 15:42:44 +0000)]
UBOOT: Booted Device-Tree:[k3-j721e-beagleboneai64.dts]
UBOOT: Loaded Overlay:[BONE-PWM0.kernel]
UBOOT: Loaded Overlay:[BONE-PWM1.kernel]
UBOOT: Loaded Overlay:[BONE-UART1.kernel]
kernel:[5.10.153-ti-arm64-r86]
I modified the ‘k3-j721e-beagleboneai64.dts’ and ‘k3-j721e-beagleboneai64-bone-buses.dtsi’ to use without adding OVERLAYS.
.dtsi file that is included by .dts
(k3-j721e-beagleboneai64.dts is also the file that BB AI-64 loads when it first boots.)
first. ( ‘k3-j721e-beagleboneai64-bone-buses.dtsi’ )
Check the expantion header pin, verify the correct pin number, and add or modify it.
BONE_PIN(P9_40, uart, P9_40B(PIN_INPUT, 14)) /* uart2_rxd */
bone_uart_4: &main_uart4 {
/* tested */
pinctrl-names = "default";
pinctrl-0 = <
&P9_38_uart_pin /* uart4_txd */
&P9_37_uart_pin /* uart4_rxd */
>;
symlink = "bone/uart/4";
status = "okay";
};
second. (k3-j721e-beagleboneai64.dts)
To enable the ports modified by dtsi, I deleted the disable contents of dts.
&main_uart4 {
/* UART not brought out */
status = "disabled";
};
Still a little confused. In my “k3-j721e-beagleboneAI64-bone-buses.dtsi” the association is as shown for P9_40 in your reply. Are you saying add the following to P9_38 and P9_39 respectively:
BONE_PIN(P9_37, uart, P9_37B(PIN_OUTPUT, 14)) /* uart4_txd /
BONE_PIN(P9_38, uart, P9_38B(PIN_INPUT, 14)) / uart4_rxd */
Do you have any explanation of why my UART5 attempt didn’t work? I may have messed up the comments for my pinctrl-0 but to late now to know since I had to restore my image.
I also don’t have a clue as to the association to “symlnk = /dev/bone/uart/4” gets a link to a certain
/dev/ttySX.
Got this working as “bone_uart_5” which maps to /dev/ttyS7. The corrected
“k3-j7221e-beagleboneai64-bone-buses.dtsi” is as follows:
bone_uart_5: &main_uart5 {
pinctrl-names = “default”;
pinctrl-0 = <
&P8_37_uart_pin /* uart2_txd /
&P8_38_uart_pin / uart2_rxd */
>;
symlink = “bone/uart/5”;
status = “okay”;
};
Per Alex Park I changed the status to “okay” from “disabled” which doesn’t require an extlinux overlay.
I have got 2 UART’s working without overlays by modifying “k3-j721e-beagleboneai64-bone-buses.dtsi” as follows:
bone_uart_2: &main_uart2 {
/* tested with sudo agetty 115200 ttyS4 /
pinctrl-names = “default”;
pinctrl-0 = <
&P9_24_uart_pin / uart2_txd /
&P9_26_uart_pin / uart2_rxd */
>;
symlink = “bone/uart/2”;
status = “okay”;
};
bone_uart_3: &main_uart5 {
pinctrl-names = “default”;
pinctrl-0 = <
&P8_37_uart_pin /* uart5_txd /
&P8_38_uart_pin / uart5_rxd */
>;
symlink = “bone/uart/3”;
status = “okay”;
};
The results is:
$ ls -al /dev/bone/uart
total 0
drwxr-xr-x 2 root root 100 Jan 1 1970 .
drwxr-xr-x 4 root root 80 Feb 18 17:00 …
lrwxrwxrwx 1 root root 11 Aug 7 2022 0 → …/…/ttyS2
lrwxrwxrwx 1 root root 11 Aug 7 2022 2 → …/…/ttyS4
lrwxrwxrwx 1 root root 11 Aug 7 2022 3 → …/…/ttyS7
I have tried the P8_17, 18 and P8_28,29, P8_31,32 with no sucess, I need a total of 3 uarts, 1 for XBEE, IMU, and GPS.
Added the following to “k3-j721e-beaglebone-bone-buses.dtsi” but still can’t get uart4 to work.
BONE_PIN(P9_37, uart, P9_37B(PIN_INPUT,14)) /* Added: uart4_rxd */
BONE_PIN(P9_38, uart, P9_38B(PIN_OUTPUT, 14)) / * Added: uart4_txd */
bone_uart_4: &main_uart4 {
/* does not work /
pinctrl-names = “default”;
pinctrl-0 = <
&P9_38_uart_pin / uart4_txd /
&P9_37_uart_pin / uart4_rxd */
>;
symlink = “bone/uart/4”;
status = “okay”;
};
$ ls -al /dev/bone/uart
total 0
drwxr-xr-x 2 root root 140 Jan 1 1970 .
drwxr-xr-x 4 root root 80 Feb 22 14:04 …
lrwxrwxrwx 1 root root 11 Aug 7 2022 0 → …/…/ttyS2
lrwxrwxrwx 1 root root 11 Aug 7 2022 1 → …/…/ttyS3
lrwxrwxrwx 1 root root 11 Aug 7 2022 2 → …/…/ttyS4
lrwxrwxrwx 1 root root 11 Aug 7 2022 4 → …/…/ttyS6
lrwxrwxrwx 1 root root 11 Aug 7 2022 2 → …/…/ttyS4
Finally got 4 UARTS working: main_uart3, main_uart5, plus main_uart0, and main_uart1. Created overlays BONE-UART3.dts and BONE_UART5.dts as bone_uart_3 and bone_uart_5 respectively. To get uart3 working I changed P9_17 to P9_27. Uart5 uses P9_38 and P9_37.
1 Like
I’ve been working on the UARTs for rs485 communication for some days, and I still can’t get main_uart4 to work properly. I can send stuff out, but I can’t receive.
You say that you have gotten main_uart5 to work on P9_38 and P9_37, but those are for main_uart4 right?
My settings for uart4 are:
BONE_PIN(P9_37, uart, P9_37B(PIN_INPUT, 8)) /* uart4_rxd */
BONE_PIN(P9_38, uart, P9_38B(PIN_OUTPUT, 8)) /* uart4_txd */
&main_uart4 {
status = “okay”;
linux,rs485-enabled-at-boot-time;
rts-gpios = <&main_gpio0 26 GPIO_ACTIVE_HIGH>;
rs485-rts-delay = <0 0>; /* note: some older versions of the driver may require at least <1 1> */
rs485-rts-active-high;
pinctrl-names = "default";
pinctrl-0 = <
&P9_38_uart_pin /* uart4_txd */
&P9_37_uart_pin /* uart4_rxd */
&P8_32_gpio_pin /* uart4_rts, but defined as gpio */
>;
};
I can see on the scope that the RTS line goes high when I send, and those transfers are good. But I can’t receive anything on uart4.
/Bo
Probably a typo. UART5 is on P8.37 & P8.38 not P9
However looking at your dts snippets, I think they are wrong.
I don’t particularly like the macro as it tends to make things harder to trace.
However for any header pin that has multiple connections to the MCU, you need to make sure that the alternative pad is configure as a GPIO input or else it is likely to interfere with what you are trying to do.
Both P9.37 and P9.38 are connected to 2 pads in this way. You are setting the B option correctly, but you also need to set the A as well, something like
BONE_PIN(P9_37, uart, P9_37B(PIN_INPUT, 8) P9_37A(PIN_INPUT, 7)) /* uart4_rxd */
BONE_PIN(P9_38, uart, P9_38B(PIN_OUTPUT, 8) P9_38A(PIN_INPUT, 7)) /* uart4_txd */
I would suggest trying that to start with. Might not be your issue of course.
I was thinking that too, but those pins do not have any “A” options, at least not as per the pin connection page, their function is just referred to as “~”
https://docs.beagleboard.org/latest/boards/beaglebone/ai-64/ch07.html#p9-36-p9-37
But I will try it.
Yep, that sure did the trick! Thanks again, you’ve been most helpful!
For reference, the new dts-settings are:
BONE_PIN(P9_37, uart, P9_37B(PIN_INPUT, 8) P9_37A(PIN_INPUT, 7)) /* uart4_rxd */
BONE_PIN(P9_38, uart, P9_38B(PIN_OUTPUT, 8) P9_38A(PIN_INPUT, 7)) /* uart4_txd */
/Bo