A new board has appeared in the family of Rock Pi 4 from Raspberry Pi alternatives – presented to our attention by CNX software. This is the Model C +, which uses low-power processor cores in its SoC to reduce the cost of its own big brother, the Model B +.
There are a few other differences in that C + has two micro HDMI ports instead of the full-size B + and does not have the built-in flash memory that is a feature of B +, but otherwise looks similar.
The SoC is a Rockchip RK3399T that has six cores. Two of them are the Cortex-A72, the type found in the Raspberry Pi 4, which runs by default at 1.5 GHz instead of 2 GHz on the OP1 in the B + model. They can, of course, be overclocked, but only up to 2 GHz, while the OP1 can run 2.4 GHz. The other four cores are Cortex-A53, seen in the Amazon Fire and Nintendo Switch tablets. They run at 1.4 GHz instead of 1.5 GHz. The graphics processor is the same Mali T860MP4 on C + and B + boards, and 4GB RAM is the same LPDDR4 running at 3200Mb / s.
Storage comes via a Micro SD card slot, although there is also an unoccupied eMMC socket that can take up to 128 GB, and the M2 socket can hold a 2TB SSD with a transfer rate limited by the PCIe 2.0 x4 interface. It has a gigabit Ethernet port, with additional HAT to add PoE capability, as well as Wi-Fi (dual-band AC) and Bluetooth. The expansion comes via two USB 3 and two USB 2 ports, plus a 40-pin GPIO array. And there is even a power button.
Speaking of which, you’ll need to power C + 5V at 5A via the USB-C port if you want to use an SSD, but the board is satisfied with 5V at 3A if you don’t. The board measures only 3.3 x 2.1 inches (85 x 54 mm) and will work with Debian, Ubuntu, Android (7, 9 or 11) officiallywith open source graphics drivers coming through Panfrost.
HDMI ports are worth looking at secondarily, as they support different resolutions. One can control 4K at 60Hz, while the other is limited to 2K at the same refresh rate. There is also a MIPI connector for additional screens and tape connectors for the camera, as long as you are fine with a maximum resolution of 8MP.