Tested with Raspberry Pi OS Release date: January 11th 2021
Go to https://www.raspberrypi.org/software/operating-systems/ page and follow the instructions to create a bootable MicroSD for Raspberry Pi. Select the lite version because the CM3-Home board doesn't have any video interface.
While booting up, the Raspberry Pi reads some configuration parameters from the first partition of MicroSD card.
These parameters are stored in a file named config.txt inside the first microSD partition.
You can edit this configuration from any PC because the first partition is formatted as FAT so it is compatible with Mac, Win an Linux. Use an ASCII editor like Nodepad or similar (please don't use Word :-) and add these lines at the end of this file:
#Ignore the HDMI cable hotplug (to avoid the delay at startup) hdmi_ignore_hotplug=1 # Set the debug port on GPIO32, GPIO33 pins force_turbo=1 dtoverlay=uart1,txd1_pin=32,rxd1_pin=33 # Enable the 1-wire bus dtoverlay=w1-gpio,gpiopin=16 # Set the audio lines on GPIO40 and GPIO41 pins dtoverlay=pwm-2chan,pin=40,func=4,pin2=41,func2=4 # Disable the Bluetooth dtoverlay=pi3-disable-bt # Set the I2C1 on GPIO 44 and GPIO 45 pins dtparam=i2c_arm=on dtparam=i2c_arm_baudrate=100000 dtoverlay=i2c1-bcm2708,sda1_pin=44,scl1_pin=45,pin_func=6 #Enable the IR Linux driver dtoverlay=gpio-ir,gpio_pin=20 #Enable the debug message enable_uart=1
It is possible to edit this file also using the Raspberry Pi itself. It is located in /boot/config.txt.
Like as config.txt also the file cmdline.txt is saved in the first microSD partition. Using the same ASCII editor change this parameter:
By default the SSH server is disabled on the Raspberry Pi OS microsd images. This could be a problem when using a CM3-Home because the video interface is not present and so if you don't have a serial cable there isn't any other way to get the access to the Linux command line.
Creating an empty file called SSH with no extention on the first microSD partition the ssh server will be enabled at first startup and you can reach the Linux command prompt via lan.
ssh firstname.lastname@example.org Password: raspberry
Your MicroSD now is ready to be used on the CM3-Home. Go to the getting started article to use it.