CH32V003 — Sub-$0.15 32-Bit RISC-V Microcontroller (48MHz, 16KB Flash)

Overview

The CH32V003 (CH32V003F4P6) is an ultra-low-cost 32-bit RISC-V microcontroller manufactured by WCH (Nanjing Qinheng Microelectronics). Available in TSSOP-20, QFN-20, SOP-16, and SOP-8 packages, it caused a sensation across the global maker community by providing a full 32-bit RISC-V core for less than $\$ 0.15 in single-unit hobbyist quantities.

Built around WCH's custom QingKe 32-bit RISC-V2A core (RV32EC) running at up to $48\text{ MHz}$ , the CH32V003 features $16\text{ KB}$ Flash, $2\text{ KB}$ SRAM, an 8-channel 10-bit $1.0\ \mu\text{s}$ ADC, a 16-bit advanced motor-control timer with complementary PWM and dead-time, standard serial buses (USART, SPI, I2C), and a proprietary Single-Wire Serial Debug Interface (1-Wire SDI / SWIO). Supported by the popular open-source bare-metal ch32v003fun framework and the official Arduino core, it has become the standard microcontroller for low-cost mass production and minimalist DIY builds.

Quick reference


CPU Core	QingKe 32-bit RISC-V2A (RV32EC Architecture)
Package Options	TSSOP-20 (CH32V003F4P6) / QFN-20 / SOP-16 / SOP-8 (CH32V003J4M6)
Max Clock Frequency	$48\text{ MHz}$ (Internal factory RC with on-chip PLL)
Flash Memory	$16\text{ KB}$ non-volatile program storage
SRAM	$2\text{ KB}$ high-speed SRAM
Supply Voltage Range	$2.7\text{ V}$ to $5.5\text{ V}$ DC (Direct 3.3V and 5.0V compatible)
GPIO Count	18 GPIOs (TSSOP-20) / 6 GPIOs (SOP-8)
Analog Peripherals	8-channel 10-bit ADC ( $1.0\ \mu\text{s}$ conversion) + Analog Op-Amp/Comparator
Advanced Timer	1x 16-bit Motor Control Timer (TIM1) with complementary PWM
Serial Bus	1x USART, 1x SPI (18 Mbps), 1x I2C (400kHz Fast Mode)
Programming / Debug	1-Wire Single-Wire Serial Debug Interface (SWIO on Pin `PD1`) via WCH-LinkE

Pinout (TSSOP-20 Package - CH32V003F4P6)

text

                       ┌───┴───┐
      (TIM1_CH1)  PD2 1│ 1   20│ PD1 (SWIO / Debug)
     (TIM1_CH2)  PD3 2│       │19 PD0 (TIM1_CH1N)
     (TIM1_CH4)  PD4 3│       │18 PC7 (USART1_TX)
         (OSC1)  PD5 4│CH32V003│17 PC6 (USART1_RX)
         (OSC2)  PD6 5│  F4P6  │16 PC5 (SPI1_SCK)
        (Active) NRST 6│ TSSOP │15 PC4 (I2C1_SDA)
           (0V)  VSS  7│  -20  │14 PC3 (I2C1_SCL)
        (+3.3V)  VDD  8│       │13 PC2 (ADC_IN2)
        (ADC0)   PA1  9│       │12 PC1 (ADC_IN1)
        (ADC1)   PA2 10│       │11 PC0 (ADC_IN0)
                       └───────┘

Pin	Name	Type	Key Multiplexed Functions
1, 2, 3	`PD2`, `PD3`, `PD4`	GPIO / Digital	`TIM1_CH1`, `TIM1_CH2`, `TIM1_CH4` / `USART1_RX`
4, 5	`PD5`, `PD6`	GPIO / Clock	External Crystal Input/Output (`OSC1`, `OSC2`)
6	`NRST`	Reset / GPIO	Active-LOW Reset / GPIO `PD7`
7	`VSS`	Power	Common Ground reference ( $0\text{ V}$ )
8	`VDD`	Power	Supply Voltage ( $+2.7\text{ V}$ to $+5.5\text{ V}$ DC)
9, 10	`PA1`, `PA2`	GPIO / Analog	`ADC_IN0`, `ADC_IN1` / `OSC32_IN`, `OSC32_OUT`
11, 12, 13	`PC0`, `PC1`, `PC2`	GPIO / Analog	`ADC_IN6`, `ADC_IN7`, `ADC_IN8`
14, 15	`PC3`, `PC4`	GPIO / Digital	`I2C1_SCL`, `I2C1_SDA` / `TIM1_CH3`
16	`PC5`	GPIO / Digital	`SPI1_SCK` / `TIM2_CH1`
17, 18	`PC6`, `PC7`	GPIO / Digital	`USART1_RX`, `USART1_TX` / `SPI1_MISO`, `SPI1_MOSI`
19	`PD0`	GPIO / Digital	`TIM1_CH1N` (Complementary PWM output)
20	`PD1 / SWIO`	GPIO / Debug	Single-Wire Debug I/O (SWIO) / Programming interface

Minimal Circuit & WCH-LinkE Flashing Hookup

text

                     +3.3V or +5.0V Regulated DC
                                 │
                          [Pin 8: VDD]
                                 │
                          [ 100nF Ceramic Bypass ]
                                 │
                          [Pin 7: VSS] ─── Common GND
                                 │
  WCH-LinkE Programmer           │
  ┌──────────────────┐           │
  │ 3.3V / 5V ───────┼───────────┘
  │ SWIO ────────────┼──────────────────────────► [Pin 20: PD1 / SWIO]
  │ GND ─────────────┼──────────────────────────► [Pin 7: VSS / GND]
  └──────────────────┘

Common mistakes

Using standard ARM SWD programmers: The CH32V003 uses WCH's proprietary 1-wire SDI protocol, not ARM 2-wire SWD. An official WCH-LinkE programmer (or an ESP32/RP2040 running an open-source 1-wire programmer firmware like minichlink) is required to flash the chip.
Pulling PD1/SWIO to ground or high-capacitance loads: Pin 20 is the sole debug interface pin. If connected to heavy capacitive loads or strong pull-downs, the programmer will fail to establish a link.

Notes

Software Ecosystem: Supported by the open-source ch32v003fun bare-metal development environment (extremely small binaries), MounRiver Studio, and the official Arduino core.