Serial Ports

• $\text{SPI}$ (Serial Peripheral Interface)
• ${\text{I}}^2\text{C}$ (Inter-IC)
• ${\text{I}}^3\text{C}$ (Inter-Inter-IC)
• $\text{UART}$ (Universal Asynchronous Reception and Transmission)
  • Since it is asynchronous, no clock is needed
  • Just has RX and TX on both sides
• $\text{CAN}$ (Controller Area Network)
• $\text{USB}$ (Universal Serial Bus)
• $\text{RS-232}$ (Recommended Standard 232)

Serial Protocols

• MAVLink

Notes

• Older Raspberry Pi SoCs have 2 UARTs - a PL011 and a mini UART
• On RPis with WiFi/BT Module, primary UART is mini UART
• On RPis without WiFi/BT Module, primary UART is PL011
• /dev/serial0 is a symlink to the primary UART
• /dev/serial1 is a symlink to the secondary UART
• /dev/ttyS0 refers to the mini UART
• /dev/ttyAMA0 refers to the PL011

NOTE

• On Raspberry Pi 4, they appear as ttyAMA0, ttyAMA1, … , ttyAMA5, when enabled (0 is already enabled)

dtoverlay=uart1
dtoverlay=uart2
dtoverlay=uart3
dtoverlay=uart4
dtoverlay=uart5

• Serial Interaction Software (for Windows)
  • SSCOM
  • NetAssist (unknown origin)
  • HW-Group Hercules SETUP Utility