Raspberry Pi Setup Notes
These notes are based on an install of the 32-bit Raspberry Pi OS Lite.
User Permissions
Note that this shouldn’t be required - by default the pi user is in the dialout, gpio, i2c and spi groups.
sudo usermod -a -G dialout pi
sudo usermod -a -G i2c pi
Development Libraries and Tools
sudo apt -y install i2c-tools libi2c-dev gpiod libgpiod2 libgpiod-dev avahi-daemon gcc make unzip zip vim git
sudo apt -y install pigpio-tools libpigpiod-if-dev libpigpiod-if2-1
Java
sudo apt -y install openjdk-11-jdk-headless openjdk-17-jdk-headless
ZSH
sudo apt -y install zsh
chsh -s /usr/bin/zsh
sh -c "$(curl -fsSL https://raw.github.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"
Make a minor tweak to the robbyrussell theme to show the hostname in the command prompt:
cd ~/.oh-my-zsh/themes
cp robbyrussell.zsh-theme robbyrussell_tweak.zsh-theme
Edit robbyrussell_tweak.zsh-theme
and change the PROMPT
value to include this prefix %{$fg_bold[white]%}%M%{$reset_color%}
. The PROMPT line should look like this:
PROMPT="%{$fg_bold[white]%}%M%{$reset_color%} %(?:%{$fg_bold[green]%}➜ :%{$fg_bold[red]%}➜ )"
Update the ZSH config ~/.zshrc
:
export PATH=$PATH:/sbin:/usr/sbin:/usr/local/sbin
export JAVA_HOME=/usr/lib/jvm/java-11-openjdk-armhf
ZSH_THEME="robbyrussell_tweak"
My own preference is to add this to the end of the .zshrc
file:
# Allow multiple terminal sessions to all append to one zsh command history
setopt APPEND_HISTORY
# Do not enter command lines into the history list if they are duplicates of the previous event
setopt HIST_IGNORE_DUPS
# Remove command lines from the history list when the first character on the line is a space
setopt HIST_IGNORE_SPACE
# Remove the history (fc -l) command from the history list when invoked
setopt HIST_NO_STORE
Check I2C Clock Speed
#!/bin/sh
# Print current maximum i2c rate
var="$(xxd /sys/class/i2c-adapter/i2c-1/of_node/clock-frequency | awk -F': ' '{print $2}')"
var=${var//[[:blank:].\}]/}
printf "I2C Clock Rate: %d Hz\n" 0x$var
Hardware PWM
All Raspberry Pi models have at least one hardware PWM channel as per the table below.
GPIO | PWM Channel | Func | Models |
---|---|---|---|
12 | 0 | 4 | All except the original model A and B |
13 | 1 | 4 | All except the original model A and B |
18 | 0 | 2 | All |
19 | 1 | 2 | All except the original model A and B |
40 | 0 | 4 | CM1-3 only |
41 | 1 | 4 | CM1-3 only |
45 | 1 | 4 | CM1-3 only |
52 | 0 | 5 | CM1-3 only |
53 | 1 | 5 | CM1-3 only |
These values were taken from the file
/boot/overlays/README
.
By default, configuring the hardware PWM channel is only possible via relatively complex memory-mapped register configuration which require root access to modify. Fortunately pigpio can handle all of this complexity for us - full hardware PWM control is available via the pigpioj provider.
Hardware PWM control is also possible via the Linux sysfs interface. To enable one hardware PWM channel add dtoverlay=pwm
to /boot/config.txt
(using the GPIO and Func values in the table above) and reboot. For example, to enable hardware PWM channel 0 on GPIO 12:
dtoverlay=pwm,pin=12,func=4
After a reboot the sysfs directory /sys/class/pwm/pwmchip0/pwm0
should be present.
Alternatively, two hardware PWM channels can be configured by adding dtoverlay=pwm-2chan
to /boot/config.txt
. For example, to enable hardware PWM channel 0 on GPIO 18 and channel 1 on 19:
dtoverlay=pwm-2chan,pin=18,func=2,pin2=19,func2=2
Make sure you add only one of the above and verify that the settings are correct before rebooting.