$1.80 CH551 Mini Development Board Features 8-bit C51 Core, USB Interface, and I/Os

Last year, WCH (Nanjing QinHeng Corp.)’s launched a CH55x family of microcontroller based on an 8-bit C51 core with a USB interface, and extra I/Os depending on the selected part number Electrodragon is now listing a tiny USB development board based on CH551 for $1.80, and the chip itself sells for as low as 1.60 RMB (0.25 USD) on Taobao. Specifications: MCU – WCH CH551 8-bit C51 micro-controller USB – 1x USB type A port I/Os – 18 through holes exposing all I/Os from the MCU including GPIOs, USB, 3.3V, 5V GND Misc – On-board power led, user LED (P3.0) Power – 5V via USB port (or pin?) You won’t need an external hardware – such as a USB to TTL board – to program the boards since the MCU supports USB. To enter into programming mode,  short connect the two pins in the middle of the board (DL) with tweezers. Electrodragon has documentation on their Wiki,  not only for …

How to Program STMicro STM8S $1 Board in Linux

In January, I discovered there was such thing as a one dollar development board based on STMicro STM8S103F3P6 8-bit MCU with 1KB SRAM, 8KB flash, and 640 bytes EEPROM, some GPIOs as well as I2C, UART, SPI, ADC, and PWM signals. Links to documentation and source code were provided, but development tools were only Windows based. However, one of my reader informed me SDCC (Small Devices C Compiler) supported STM8, and development in Linux should be feasible. So I decided to buy the board on eBay for $1.62, as well as an ST_link V2 programmer for STM8 / STM32 for $4.52 in order to flash the firmware. The board came pretty quickly, i.e. within 2 to 3 weeks. But due to a lost package, the programmer took nearly 3 months to reach me, as the seller had to re-send after I failed to receive it within 2 months. It comes with 4 wires that need to be connected to RST/NRST, …