Published May 17, 2023 © LGPL

Alternative Raspberry Pi board

For several months now, it has become impossible to buy a Raspberry Pi from official resellers, the alternative is Rock 4 SE

IntermediateProtip1 hour1,609

Things used in this project

Hardware components

Radxa Rock 4 SE

Dual CAN BUS Shield for Raspberry

Software apps and online services

Snappy Ubuntu Core

Story

For several months now, it has become impossible to buy a Raspberry Pi from official resellers, this situation has a very heavy impact on the world of makers and industries, also on our business. After weeks of searching we have found an alternative Single Board Computer compliant with a part of our boards ROCK 4 SE.

ROCK 4 SE is a Single Board Computer (SBC) in an ultra small form factor that offers class leading performance and an extensive range of expansion ports. The ROCK 4 SE offers professionals, industrial OEMs, IoT enthusiasts, hobbyists, PC DIY enthusiasts and makers a reliable and extremely capable platform for building and tinkering their ideas into reality. ROCK 4 SE is available in 4GB LPDDR4 RAM option.

ROCK 4 SE Product Brief

The complete features are described on official wiki

If you check the Rock 4 board pinout carefully, you can discover that it is not fully complaint with Raspberry Pi, our boards Dual Can requires the following peripherals:

SPI with 2 Chip select on pins 19, 21, 23, 24 and 26
I2C for RTC on pins 3 and 5
2 interrupts on pins 15 and 22

On the following table you can see that the second SPI chip select is not available on pin 26 for ROCK 4 SE board.

Software configuration

It is possible to install 3 different Operating Systems:

Android, Debian and Ubuntu Server.

For our test we have downloaded Ubuntu Server 20, follow the official wiki for SD card preparation.

Modify file /boot/hw_intfc.conf. Set “on” to enable the optional hardware interfaces while set “off” to disable.

sudo nano /boot/hw_intfc.conf

Enable the following overlays:

intfc:i2c7=on

intfc:spi1=on

intfc:dtoverlay=mcp2515-can0-SG

Save and exit and reboot the board with sudo reboot

Overlay customization

The Ubuntu image contains the following overlay dtbo files (dts file download)

at24c02.dtbo

console-on-ttyS4.dtbo

console-on-ttyS2.dtbo

cpufreq.dtbo

devspi1.dtbo

devspi2.dtbo

imx219.dtbo

pcie-gen2.dtbo

raspberrypi-7-inch-lcd.dtbo

rk3399-usb-host.dtbo

rk3399-usb-otg.dtbo

rock-4c-plus-raspberrypi-7inch-touchscreen.dtbo

rock-4c-plus-radxa-display-8hd.dtbo

rock-4c-plus-radxa-display-10hd.dtbo

spi1-waveshare35c.dtbo

spi1-waveshare35b-v2.dtbo

spi1-flash.dtbo

spi1-mcp2515-can0.dtbo

two-color-led.dtbo

w1-gpio4-30.dtbo

The spi1-mcp2515-can0.dtbois not correct has the following problem: clock-frequency = <12000000>; Our board works with a 16 Mhz oscillator, then we must generate a custom file mcp2515-can0-SG.dtbo.

For dtbo generation you must install the device tree compiler

sudo apt update

sudo apt install device-tree-compiler

sudo apt install can-utils

cd /boot/overlays

sudo /usr/bin/dtc -I dts -O dtb -o mcp2515-can0-SG.dtbo -I dts mcp2515-can0-SG.dts

sudo reboot

After the board startup use the following command to start can0 interface

sudo ip link set can0 up type can bitrate 1000000

ifconfig

CAN BUS Test

Test 1: Raspberry Pi CAN TX —-> Rock Pi CAN RX

Raspberry Pi run the command

cangen can1

instead on Rock Pi run

candump can0

If the device trees on both boards are correctly configured and the can adapters are correctly connected you can see the message log under candump terminal.

For further details visit our web page

mcp2515-can0-SG.dts

/* This devicetree overlay is INT pin 15 is GPIO4_C5 --> 4 A= 0, B = 1, C=2, D=3
* Pin is 4 C*8+5 ---> rockchip,pins = <4 21 0 &pcfg_pull_none>;
* Device tree overlay for mcp251x/can0
*/
/dts-v1/;
/plugin/;

/ {
        compatible = "rockchip,rockpi","rockchip,rk3399", "rockchip,rk3399-pinctrl";

        fragment@0 {
                target = <&pinctrl>;

                __overlay__ {
                        mcp2515_int_pin: mcp2515_int_pin {
                                rockchip,pins = <4 21 0 &pcfg_pull_none>;
                        };
                };
        };

        fragment@1 {
                target-path = "/";
                __overlay__ {
                        can_mcp2515_osc: can-mcp2515-osc {
                                compatible = "fixed-clock";
                                clock-frequency = <16000000>;
                                #clock-cells = <0>;
                        };
                };
        };

        fragment@2 {
                target = <&spi1>;

                __overlay__ {
                        status = "okay";
                        max-freq = <10000000>;
                        #address-cells = <1>;
                        #size-cells = <0>;

                        can_mcp2515: can-mcp2515@0 {
                                status = "okay";
                                compatible = "microchip,mcp2515";
                                reg = <0>;
                                interrupt-parent = <&gpio4>;
                                interrupts = <21 2>;
                                spi-max-frequency = <10000000>;
                                clocks = <&can_mcp2515_osc>;
                                vdd-supply = <&vcc3v3_sys>;
                                xceiver-supply = <&vcc3v3_sys>;
                                pinctrl-names = "default";
                                pinctrl-0 = <&mcp2515_int_pin>;
                        };
                };
        };
};

Credits

Pier8283

10 projects • 5 followers

Alternative Raspberry Pi board

Things used in this project

Hardware components

Software apps and online services

Story

Software configuration

Overlay customization

CAN BUS Test

Code

mcp2515-can0-SG.dts

Credits

Pier8283

Comments

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Alternative Raspberry Pi board

Alternative Raspberry Pi board

Things used in this project

Hardware components

Software apps and online services

Story

Software configuration

Overlay customization

CAN BUS Test

Code

mcp2515-can0-SG.dts

Credits

Pier8283

Comments

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