Dev kit unlocks secrets of 1TOPS Kendryte RISC-V chip

Sipeed’s $24.90 “Sipeed MaixCube” dev kit runs FreeRTOS or Linux on a Kendryte K210 RISC-V with 1TOPS NPU via Sipeed’s M1n module. The kit has a display, camera, mic, and battery plus Grove and Sipeed’s SP-MOD interfaces.

Sipeed has gone to Seeed to open $24.90 pre-orders for a Sipeed MaixCube development kit based on its M1n module, an updated version of the M1 (or MAIX-I) module found on Seeed’sGrove AI HAT for the Raspberry Pi. The Sipeed MaixCube is an all-in-one kit with a display, camera, mic, battery, and other functions all packed into a plastic, portable case

Like the M1, the M1n module provides a dual-core, 400MHz Kendryte K210 RISC-V processor with an AI chip for accelerating AI inference on the edge. Applications include face detection, object recognition, FFT spectrogram, and game simulations.

Whereas the M1 is a castellated edge module, the M1n connects to a carrier board via a non-standard M.2 edge interface that links to a USB Type-C adapter. Another difference is that the M1 is available in a WiFi version while the M1n is not. The low-power M1/M1n modules are typically paired with WiFi, as they are on the Grove Pi Hat, using the Raspberry Pi’s WiFi, or on the Arduino Uno form-factor Sipeed Maixduino board, which combines an M1 with an ESP32 module. However, the MaixCube lacks WiFi or Ethernet.

The 64-bit Kendryte K210 SoC on the M1n supplies an FPU, 8MB RAM, and an audio processor unit (APU) that supports up to 8-mic input. The chip supports QVGA image recognition @ 60fps and VGA @ 30fps.

Seeed lists both FreeRTOS and Linux as embedded operating systems that run on the Sipeed MaixCube, but the M1n product page lists only FreeRTOS. According to the CNXSoft story that alerted us to the MaixCube, “Linux is probably less useful since AFAIK AI accelerators have not been implemented in Linux.”

The default development environment is the pre-installed, open source MaixPy firmware, which has Micropython functional libraries that developers can call directly. This works together with a desktop MaixPy IDE that lets you view camera images in real-time and save files to the MaixCube. Developers can also use ArduinoIDE and PIatformIO IDE using C++.

The 40 x 40 x 16mm MaixCube is equipped with a microSD slot, 128Mbit flash, and a USB Type-C port for power input or charging up the 200mAh Lithium battery. One side of the box holds the 1.3-inch TFT screen while the other has a VGA camera. Other features include an electret microphone, an accelerometer, a speaker output, a 3-way button, 2x LEDs, and reset and power buttons.

Two expansion interfaces are available: a Seeed Grove interface and an SP-MOD (SiPeed MODule) interface. SP-MOD has an 8-pin header with Vcc, GND, and “6 signals.” There are 14 SP-MODs to choose from including a mic array, weather station, USB, LCD, Bluetooth, and LoRa options.