When you see a 20mm square with a big IC on it, you might assume it is a microcontroller. HaneSOM from DAB-Embedded is an Arm Cortex A5-based compute module capable of running Linux with a single 3.3 volt supply!
Despite only measuring 20 by 20mm, HaneSOM is a fully functional Linux computer. The core processor is a Microchip SAMA5D2 with 1 Gbit DDR2 RAM with 69 I/O pins available. Onboard is a bootable 32 Mbit QSPI and PMIC. The MIC2800 power controller is how HaneSOM runs off of a single volt rail. (Although some peripherals may need other voltage rails.)
Like a 32-bit microcontroller, the SAMA5D2 has a wide array of I/O interfaces. For example, it can drive a 24-bit RGB LCD directly, support a 5-megapixel camera sensor, I2S audio, capacitive touch controller, USB 2.0, Ethernet, 12-bit ADC, and low-speed serial (e.g., SPI, I2C, USART.)
With so much connectivity, HaneSOM can be the core of an edge machine learning device, the heart of an IoT gateway, or the start of an internet-connected camera.
Software support includes Yacto, Buildroot, OpenWRT, and Baremetal. Even with Linux running, the current consumption is only 150 milliamps while idle.
On HaneSOM's Tindie Page, you can find schematics, a manual, and a complete pinout of its I/O pins. HaneSOM is now available and sells for $37 USD.