List of possible standards to follow, towards a more extensible board design.
Raspberry Pi #
- Raspberry Pi Pinout
- Raspberry Pi HATs, pHATs & Add-ons
- A whole bunch of standard serial interfaces and GPIOs—suitable for powerful boards.
96Boards (by Linaro) #
- 96Boards Pinout
- 96Boards add-on boards
- Unless otherwise indicated the connector signals are at 1.8 V logic levels.
BeagleBone Black #
- Beagleboard:Cape Expansion Headers - eLinux.org
- BeagleBoard.org Capes - BeagleBoard.org
- Falls short in popularity.
Arduino Uno R3 #
- Pinout of Arduino Board and ATMega328PU - Wikimedia Commons
- Arduino Shields - Adafruit
- Arduino Shields - Sparkfun
- Uno and its AVR-based variants operate at 5 V; ARM-based variants operate at 3.3 V. We should watch out for potential signal level mismatch issues.
- Contains analog pins, usually suitable for microcontroller boards.
Arduino MKR #
- Arduino MKR1000 Wi-Fi Board Pinout - Components101
- MKR Family - Arduino
- Contains analog pins, usually suitable for microcontroller boards.
Feather (by Adafruit) #
- Feather - Adafruit
- Introducing Adafruit Feather - Adafruit
- Contains analog pins, usually suitable for microcontroller boards.
XBee (by Digi) #
- Digi XBee3 RF Module Hardware Reference Manual - Digi
- Products Tagged “Digi XBee” - Digi
- The World of Digi XBee - Digi-Key
- XBee - Adafruit
- XBee - SparkFun
- Single power supply pin, VCC, usually connects to 3.3 V.
- 2.0 mm pitch, not friendly for breadboard prototyping.
- Existing add-on boards are kind of limited to wireless modules.
mikroBUS (by MikroElektronika) #
- mikroBUS™ - MikroElektronika
- Created by MikroElektronika, mikroBUS™ is an open standard—anyone can implement mikroBUS™ in their hardware design, as long as the requirements set by this document are being met.
- Production-grade standard clarity and design files.
- Click Boards - MikroElektronika
- Wide variety of add-on boards.
- Mostly come with schematic.
- Connects to Raspberry Pi through Pi 3 Click Shield.
- Connects to Arduino Uno through Arduino Uno Click Shield.
- Connects to Arduino Mega through Arduino Mega Click Shield.
- There are Shuttle click and mikroBUS Shuttle when the space is tight.
- Dual power supply pin, 5 V and 3.3 V.
- Adopted by various vendors.
- Looks GREAT for primarily digital, lightweight designs.
Pmod (by Digilent) #
- Pmod™ - Digilent
- Maximum of one standard serial interface in each connector—suitable for FPGA boards whose pin functions are easily configurable, don’t have to worry about pinmux.
Grove (by Seeed) #
- Grove System - Seeed
- Maximum of one standard serial interface in each connector.
- Uses 4-pin connector, it could contain UART, I2C, but not SPI.
- 2.0 mm pitch, non-JST connector, not friendly for breadboard prototyping.
STEMMA (by Adafruit) #
- STEMMA / STEMMA QT Comparison - Adafruit
- Uses 3/4-pin, 2.0 mm pitch, JST PH-series connector.
- Attempts to be as cross-compatible as possible with both Grove and (DFRobot) Gravity.
- Modules are mostly breadboard-friendly, but lack of unified form factor.
Qwiic (by SparkFun) #
- Qwiic Connect System - SparkFun
- Specifically designed for I2C.
- Uses 4-pin, 1.0 mm pitch, JST SH-series connector.
- Modules are mostly breadboard-friendly, but lack of unified form factor.
STEMMA QT (by Adafruit) #
- STEMMA / STEMMA QT Comparison - Adafruit
- Uses 4-pin, 1.0 mm pitch, JST SH-series connector.
- Cross-compatible with Qwiic.
- Modules are mostly breadboard-friendly, but lack of unified form factor.