SiFive
Microcontrollers use the open-source RISC-V instruction set.
HiFive1 Rev B
The HiFive1 Rev B is SiFive’s second revision of their first development kit. It carries a FE310-G002 Freedom Everywhere SoC (System on Chip).
   Specifications
| Parameter | Value | 
|---|---|
| Input Voltage | USB 5V or 7-12V via DC jack | 
| IO Voltage | 3.3V | 
| Flash Memory | 32Mbit (external via SPI) | 
| Clock Speed | 320MHz | 
| Digital IO Pins | 19 | 
| PWM Pins | 9 | 
| UART | 2 | 
| I2C | 1 | 
Suppliers
Can be purchased from:
- CrowdSupply for US$59 (as of Dec 2020)
 - Mouser for US$59 (as of Dec 2020)