This documentation is constantly updated as I learn and practice new areas in the domain of Embedded Linux, networking, troubleshooting and best practices. And also this will serve as a short-note for all the commands and research I'm doing. And I wish this shall be a knowledge hub for anyone interested in these topics

Linux-based Embedded Systems

Networking

Networking Fundamentals

How a ping works based on Debian/ubuntu systems and raspbian systems

Sharing Internet over Ethernet

WiFi

4G

RK3568

This is sort of a log on the go, while settin up the SOM. I noted down to repetitive commands and procedures here.

Drive link https://ln5.sync.com/dl/633f463c0/w5f2hutx-nvggz3wv-3gv8pr53-9jcr7kq2

Device Tree https://www.linkedin.com/pulse/device-trees-embedded-linux-keroles-khalil/

Setting Up dev board with custom config

Uploading base image and kernel

linux PC Connect serial cable to host PC Connect microusb cable to host PC Press turn off power , press vol+ button and turn on power use rkchip commands from host PC to rotate

uploading damin image sudo ./upgrade_tool uf update-debian.img

uploding kernel you can upload the kernel seperately sudo ./upgrade_tool di -b boot.img sudo ip -details link show can0

Systemd services

sudo systemctl enable my-service.service sudo systemctl start my-service.service

Connect to internt using nmcli/nmtui

Useful commands nmcli device wifi list nmcli device wifi connect "SSID_NAME" password "YOUR_PASSWORD" nmcli connection modify "SSID_NAME" connection.autoconnect yes

Adding dabian pacakages to source

sudo nano /etc/apt/sources.list

# Debian 10 Buster repositories
deb [arch=arm64] http://deb.debian.org/debian/ buster main contrib non-free
deb [arch=arm64] http://deb.debian.org/debian/ buster-updates main contrib non-free
deb [arch=arm64] http://deb.debian.org/debian-security buster/updates main contrib non-free.debian.org/debian-security buster/updates main contrib non-free

Setting windowing server

There are two types of servers. X11(Xorg) or walyland Find your server using echo $XDG_SESSION_TYPE. You have to fun this in grahical interface to find out. if you use login console, what you will get of tty. X11uses .xinitrc in home (~) when called by startx or xinit. Sample file is located at /RK3568/windowing server. startx can be run at boot by adding the command to ~/.bash_profile

XOrg Server Xor is the

sudo apt-get install --no-install-recommends xserver-xorg x11-xserver-utils xinit openbox

Disabling light display manager You have to disable your desktop environment using systemctl disable lightdm. Once you do, after a boot your desktop env will not appear. But still the windowing server is directed to light dm. you can verify it by running startx which immediately opens up your lightdm destop env.

Installing lightweight browser

I used Midori browser.

 sudo apt-get install midori

Configuration for that browser is located at ~/.config/midori/config

screen rotate xrandr --output HDMI-1 --rotate left

Configure CAN

canfd-1.0:

CAN FD (Flexible Data-rate): canfd-1.0 refers to CAN controllers that support the CAN FD protocol, which is an extension of the classic CAN protocol. CAN FD allows: Higher data rates (up to 8 Mbps, compared to the classic CAN 1 Mbps limit). Larger payloads per frame (up to 64 bytes instead of 8 bytes in classic CAN). The canfd-1.0 designation likely refers to a CAN FD controller version supported by Rockchip or a similar standard (e.g., Bosch CAN FD 1.0). In your DTS snippet, can0 and can2 are using canfd-1.0, which suggests they support CAN FD. can-1.0:

Classic CAN: can-1.0 represents controllers that support the standard or "classic" CAN protocol. Classic CAN has a lower data rate and is limited to 8 bytes per frame. This controller type is typically sufficient for standard automotive and industrial CAN applications where high data rates or larger payloads aren’t required. In your DTS snippet, can1 is designated as can-1.0, indicating it only supports the classic CAN protocol.

can0: can@fe570000 { compatible = "rockchip,canfd-1.0"; reg = <0x0 0xfe570000 0x0 0x1000>; interrupts = <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>; clocks = <&cru CLK_CAN0>, <&cru PCLK_CAN0>; clock-names = "baudclk", "apb_pclk"; resets = <&cru SRST_CAN0>, <&cru SRST_P_CAN0>; reset-names = "can", "can-apb"; tx-fifo-depth = <1>; rx-fifo-depth = <6>; status = "disabled"; };

can1: can@fe580000 {
    compatible = "rockchip,canfd-1.0";❌️
    compatible = "rockchip,can-1.0";✅️
    reg = <0x0 0xfe580000 0x0 0x1000>;
    interrupts = <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>;
    clocks = <&cru CLK_CAN1>, <&cru PCLK_CAN1>;
    clock-names = "baudclk", "apb_pclk";
    resets = <&cru SRST_CAN1>, <&cru SRST_P_CAN1>;
    reset-names = "can", "can-apb";
    tx-fifo-depth = <1>;
    rx-fifo-depth = <6>;
    status = "disabled";
};

can2: can@fe590000 {
    compatible = "rockchip,canfd-1.0";
    reg = <0x0 0xfe590000 0x0 0x1000>;
    interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
    clocks = <&cru CLK_CAN2>, <&cru PCLK_CAN2>;
    clock-names = "baudclk", "apb_pclk";
    resets = <&cru SRST_CAN2>, <&cru SRST_P_CAN2>;
    reset-names = "can", "can-apb";
    tx-fifo-depth = <1>;
    rx-fifo-depth = <6>;
    status = "disabled";
}; what is canfd-1.0 and can-1.0