The Raspberry Pi 4 is a pretty cool board, but if you wished it was just a bit smaller, and you could use the PCIe interface exposed by the Broadcom BCM2711 processor more easily, Timon has designed Piunora carrier board for the Raspberry Pi Compute Module 4.
The solution provides a board with the guts of Raspberry Pi 4 SBC but using the Arduino form factor including access to the six ADC pins, and an M.2 socket with the PCIe signal from the Broadcom SoC.
Piunora carrier board specifications:
- SoM compatibility – Raspberry Pi CM4 module with Broadcom BCM2711 quad-core Cortex-A72 processor @ 1.5 GHz, 1 to 8GB RAM, optional 4GB to 32GB eMMC flash, optional wireless module with 802.11b/g/n/ac WiFi 5 and Bluetooth 5.0
- Storage – 1x MicroSD card socket (for the OS when using Raspberry Pi CM4Lite system-on-module)
- Video Output – 1x HDMI 2.0 port up to 4Kp60
- Camera I/F – MIPI camera connector
- USB – 1x USB 2.0 port, 1x USB-C port with support for data and power; device/host switch.
- Arduino compatible header with markings – 6x ADC, digital I/Os, I2C, SPI, UART, etc…
- Qwiic/Stemma QT connector
- M.2 B-key socket with PCIe signals
- Misc – 4x RGB LEDs, dual-mode button (user/boot mode for flashing eMMC flash)
- Power Supply
- 5V via USB-C port (board power)
- Extra USB-C port (bottom side) for optional power-in for very high current M.2 devices
- Dimensions – Adafruit Metro / Arduino UNO form factor
Most Raspberry Pi 4 applications would be suitable for the board, but Timon designed it specifically with CircuitPython in mind, as he intends to mount the Pi as a USB gadget instead of a host device, and follow the same development workflow as a normal MCU development board directly on the computer. The board will be open-source hardware with all design files released once shipping starts.
Two versions of the board are offered with the full-featured Piunora Pro, as well as Piunora Lite with a thinner form factor that removes the camera connector and the PCI-e M.2 port. As a side note, one of the photos shows a Raspberry Pi RP2040 board that slots into the M.2 socket, but no details are provided at this time.
Piunora has just launched on Crowd Supply with a $15,000 funding goal. Rewards start at $30 for Piunora Lite, and $39 for Piunora Pro. You’d still need a Raspberry Pi CM4/CM4Lite module to have a working system, and some are offered on Crowd Supply. Shipping adds $8 to the US, and $18 to the rest of the world with deliveries scheduled to start at the end of June.
[Update: This article was initially published on December 24, 2020, and updated on March 31, 2021, with the launch of Piunora on Crowd Supply]