Polos CH32Vxx 32-bit RISC-V MCU boards starts at $1.99

XPU Labs, a subsidiary of AnalogLamb, has designed three inexpensive “Polos” development boards based on WCH CH32VXX RISC-V microcontrollers with pricing starting at just $1.99.

The three development/breakout boards have the same form factor and only differ in the specific RISC-V MCU used with three parts selected: the 48 MHz CH32V003F4U6 microcontroller, the 144 MHz CH32V203F8P6 MCU, and the CH32V305FBP6 that’s similar to the former but add more memory (32KB) and flash (128KB). You can see also three boards side-by-side in the photo below along with the Amnos LinkE CH32Vxx debugger & programmer board.

Polos CH32V003 Breakout Alef specifications:

• MCU – WCH CH32V003F4U6 QingKe 32-bit RISC-V2A microcontroller up to 48MHz with 2KB SRAM, 16KB Flash (QFN20 Package)
• USB – 1x Micro USB port
• I/Os – 2x 12-pin headers with
  • Up to 18 GPIOs with external interrupt support
  • 1x USART, 1x I2C, 1x SPI
  • 10-bit ADC
• Debugging – 1-wire serial debug interface (SDI)
• Misc – 2x 16-bit timers, DMA, OP Amp, 64-bit chip unique ID
• Power Supply – 5V via USB-C port; 5V/3.3V circuit voltages
• Dimensions – Small

Polos CH32V203F8 Breakout Alef specifications

• MCU – WCH CH32V203F8P6 QingKe 32-bit RISC-V4B microcontroller up to 144MHz with 20KB SRAM, 64KB Flash (TSSOP20 Package)
• USB – 1x USB Type-C port
• I/Os – 2x 12-pin headers with
  • Up to 17x GPIOs with 16x external interrupts
  • 2x USART, 1x I2C, 1x SPI
  • 2x 9-ch 12-bit ADC
  • USB 2.0 FS
• Debugging – 2-wire serial debug interface
• Misc – 2x 16-bit timers, 18-ch DMA, 2x OP Amps, CRC calculation unit, 96-bit unique ID
• Power Supply
  • 5V via USB-C port
  • 3.3/2.5 circuit voltages
  • Low-power modes – Sleep, Stop, and Standby
  •  Consumption
    • Down to 44.65uA/MHz in Run mode
    • Down to 17.90uA/MHz in Sleep mode
• Dimensions – Small

Polos CH32V305 Breakout Alef specifications:

• MCU – WCH CH32V305FBP6 QingKe 32-bit RISC-V4F microcontroller up to 144MHz with 32KB SRAM, 128KB Flash (TSSOP20 Package)
• USB – 1x USB Type-C port
• I/Os – 2x 12-pin headers with
  • Up to 17x GPIOs with 16x external interrupts
  • 2x USART, 1x I2C, 1x SPI
  • 2x 1-ch 12-bit ADC, 1x 12-bit DAC
  • USB 2.0 FS
  • CAN Bus
  • Touch key
• Debugging – 2-wire serial debug interface
• Misc – 8x timers, 2x 9-ch DMA, CRC calculation unit, 96-bit unique ID
• Power Supply
  • 5V via USB-C port
  • 3.3/2.5 circuit voltages
  • Low-power modes – Sleep, Stop, and Standby
• Dimensions – Small

There’s not much in the way of documentation with a GitHub repository featuring the PDF schematics for two of the boards and users are simply told to use the MounRiver Studio IDE for programming.

But the Polos boards from XCPU Lab are not the first cheap RISC-V MCU boards with MuseLabs nanoCH32V003 selling for $1.50 plus shipping, and specifications quite similar to the ones for the Polos CH32V003 Breakout Alef. At the time, I noted two ways of developing firmware for the board:

the usual MounRiver Studio IDE and WCH-LinkUtility for the WCH-LinkE downloader/debugger, and an open-source toolchain based on GCC named xPack RISC-V Embedded GCC along with samples…

Both those methods should work on the Polos boards too, and a third option is to use CNLohr’s CH32V003fun open-source development environment, but it was only developed for the CH32V003 parts, so the more powerful CH32V305/7 and CH32V203 RISC-V might not be supported, especially they rely on different RISC-V4B and RISC-V4F implementations.

Pricing for the Polos boards goes as follows:

• Polos CH32V003 Alef – $1.99
• Polos CH32V203F8 Alef – $3.49
• Polos CH32V305 Alef – $4.99

You’ll find all three on AnalogLamb’s store, but you’ll also need the Amnos LinkE Breakout for debugging and programming which adds $4.99 extra.

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