These evolving personal notes document my journey and discoveries as I explore the versatile Raspberry Pi. At present, all information pertains specifically to the Raspberry Pi 5.
Power
- Minimum required: 5V / 3A (can’t connect any bus-powered HDDs/SSDs)
- Best performance: 5v / 5A
Remainder: x Volt * y Amp = z Watt
Pogo Pin: A pogo pin is a spring-loaded connector used to create reliable electrical connections in electronics without the need for soldering, commonly for programming and connecting peripherals.
Firmware
# Get current firmware
vcgencmd version
# Update Raspberry firmware
rpi-update
# Get bootloader details
sudo rpi-eeprom-update
# Update bootloader
sudo rpi-eeprom-update -a
Networking
In Raspberry Pi OS 12 and later, dhcpcd is no longer used, everything goes through Network Manager, which is configured via nmcli or nmtui.
# View status
nmcli device status
# View NIC details
nmcli device show eth0
# Configure networking
sudo nmtui
# Apply changes
sudo systemctl restart NetworkManager
Memory
Swap
Swap provides extra virtual memory using disk space when RAM is full, helping prevent crashes on memory-limited devices like the Raspberry Pi. This section shows how to resize your swap space to better handle memory-intensive tasks.
# Turn off the current swap
sudo dphys-swapfile swapoff
# Edit the swap configuration file
sudo vim /etc/dphys-swapfile
# Increase the swap size
CONF_SWAPSIZE=1024
# Apply the new swap size
sudo dphys-swapfile setup
# Turn the swap back on
sudo dphys-swapfile swapon
Real-Time Clock
The integrated Real Time Clock (RTC) feature allows many scenarios, the most common of which is the ability to set wake-up alarms that allow the board to enter an ultra-low power state, consuming only about 3mA.
Wake-up alarms
Under the hood, the file /sys/class/rtc/rtc0/wakealarm is the thing that tells the pi when to wake up next time. And all it is is a long number written in epoch time (seconds since 1970). If that number is 10 minutes in the future, then when the RTC clock reaches that number, it will tell the Pi to turn itself on (if the Pi is off). If the Pi was on during this time, nothing will happen.
Enabling low-power mode is a simple change to the bootloader configuration.
sudo -E rpi-eeprom-config --edit
Add the following lines to the configuration file
POWER_OFF_ON_HALT=1 WAKE_ON_GPIO=0
Test the wake functionality with the commands
echo +600 | sudo tee /sys/class/rtc/rtc0/wakealarm
sudo halt
It is important to note that the RTC function remains accessible even without a backup battery connected to the J5 connector.
Battery
When choosing a battery, care should be taken not to use a primary lithium cell due to potential problems with the trickle charge circuit. The recommended choice is a rechargeable Lithium-Manganese cell, designed for long life and optimum performance. Equipped with a two-pin JST connector and adhesive mounting pad, this battery ensures that the RTC will continue to operate seamlessly when the primary power supply is disconnected.
Trickle charging
Trickle charging is disabled by default, but can be enabled by adding a line to the /boot/firmware/config.txt file:
dtparam=rtc_bbat_vchg=3000000
After a reboot, you’ll see the charge voltage change, indicating that the battery is now being trickled charged.
Hardware
Geekworm X1011
Is a PCIe to NVMe Shield support 4x M.2, offical wiki page, it just works, nothing to do after following the mounting instructions.
lspci
0000:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries Device 2712 (rev 21)
0000:01:00.0 PCI bridge: ASMedia Technology Inc. ASM1184e 4-Port PCIe x1 Gen2 Packet Switch
0000:02:01.0 PCI bridge: ASMedia Technology Inc. ASM1184e 4-Port PCIe x1 Gen2 Packet Switch
0000:02:03.0 PCI bridge: ASMedia Technology Inc. ASM1184e 4-Port PCIe x1 Gen2 Packet Switch
0000:02:05.0 PCI bridge: ASMedia Technology Inc. ASM1184e 4-Port PCIe x1 Gen2 Packet Switch
0000:02:07.0 PCI bridge: ASMedia Technology Inc. ASM1184e 4-Port PCIe x1 Gen2 Packet Switch
0000:03:00.0 Non-Volatile memory controller: Intel Corporation SSD Pro 7600p/760p/E 6100p Series (rev 03)
0001:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries Device 2712 (rev 21)
0001:01:00.0 Ethernet controller: Device 1de4:0001