Just as I was finishing my previous article about a new TI microcontroller that was smaller than a grain of white rice and sold for 16 cents in thousand-unit quantities, I learned of another new microcontroller based on a proprietary implementation of the 32-bit RISC-V processor ISA that sells for 10 cents (presumably in volume). This new microcontroller from WCH, aka Nanjing Qinheng Microelectronics, a Chinese chip and IP vendor based in Nanjing, China. (“WCH” appears to be an abbreviation for “WinChipHead.”) The microcontroller is the WCH CH570, which has 12 Kbytes of on-chip SRAM and 240 Kbytes of Flash EEPROM for user code. It also integrates internal controllers and PHYs for USB 2.0, 2.4GHz wireless, and Bluetooth Low Energy (BLE) 5.0. How could I resist looking into something like that?
WCH is an experienced microcontroller vendor and IP developer. The company started designing microcontrollers based on its proprietary implementation of an 8-bit 8051 processor core. It then progressed to using 32-bit Arm Cortex-M0 and -M3 cores and is now developing multiple microcontroller chips based on its own RISC-V processor core IP. The company’s “about” tab on its Web site says that WCH “focuses on connectivity technology and microprocessor research and is an IC design company that designs chips based on self-developed professional interface IP and microprocessor IP. We provide USB/ Bluetooth /Ethernet interface chips, alongside connectivity/interconnectivity/wireless MCUs integrated with these interfaces.”
So far, marketing for the CH570 microcontroller consisted of the following post on X from WCH’s Patrick Yang:
“Hey geeks! To bring AI into the last 100 meters of daily life, we’re launching the CH570—a RISC-V 32-bit SoC with 2.4GHz wireless and USB 2.0 (Host & Device). It’s an upgrade from the CH32V003, with more features at the same low price—still just about a dime (10 cents).”
Supposedly, WCH will be selling chips and development boards on AliExpress, and the company does list many of its products on AliExpress, but at the time of my writing this article, a CH570 product page was nowhere to be found there. Nevertheless, a look at the data sheet, which I had to find using Google, convinced me that this microcontroller was worth an article. Be forewarned. The CH570 microcontroller is obviously aimed at the domestic market in China. Caveat emptor.
A block diagram of the CH570 microcontroller appears below.
Block diagram of WCH’s CH570 microcontroller with support for 2.4GHz and Bluetooth Low Energy (BLE). Image credit: WCH
The processor core in WCH’s CH570 microcontroller is a QingKe RISC-V3C. WCH has developed a series of processor cores based on the RISC-V ISA under the QingKe brand. The QingKe RISC-V3C core implements the RV32IMCB variant of the RISC-V ISA. That means that it’s a 32-bit integer-only core with support for multiplication and division instructions, bit-manipulation instructions, and a compressed 16-bit set of instructions. WCH provides a separate 48-page manual for the QingKe V3 microprocessor family.
The QuingKe RISC-V3C core design has a 3-stage pipeline that runs at a maximum clock rate of 100MHz. There’s no cache memory. Instead, the processor core runs code directly from the microcontroller chip’s on-chip Flash EEPROM, with a capacity of 240 Kbytes for code and static data and an additional 8Kbyte bootloader ROM. There’s a 12Kbyte SRAM for volatile data storage, and the processor and on-chip DMA activity can access the SRAM through a WCH-developed arbiter. The SRAM can retain data when the processor enters sleep mode.
In the microcontroller block diagram above, you’ll see a typical set of peripheral devices in the diagram’s upper left quadrant, including GPIO pins, serial ports (UART, SPI, I2C), a timer with PWM control, and a real-time clock. Although the peripherals appearing to the left of the processor core seem pretty standard, the three peripheral devices appearing below the processor core in the above block diagram are not standard for such a low-cost microcontroller. The block appearing immediately below the processor core is a self-explanatory USB 2.0 controller. The block marked “Keyscan” is a keyboard/keypad scanner capable of automatically scanning as many as 20 keys through the matrixed use of five GPIO pins. The Keyscan module can continue scanning keys while the processor is in sleep mode, which can greatly reduce power consumption. However, it’s the other peripheral, the one marked “RF Transceiver” that bears special mention, I think. This 10-cent microcontroller supports 2.4GHz wireless and Bluetooth BLE 5.0 directly, as evidenced by the pin labeled “ANT” (antenna). I suspect that this low-cost microcontroller is going to be the foundation of many wireless IoT devices designed in China.
It’s not at all surprising to see microcontrollers based on the RISC-V ISA coming from a Chinese semiconductor maker. The RISC-V ISA is swiftly becoming the official processor ISA of the Chinese microprocessor ecosystem. In fact, Reuters recently reported that a group of eight Chinese governing organizations – including the Cyberspace Administration of China, China’s Ministry of Industry and Information Technology, the Ministry of Science and Technology, and the China National Intellectual Property Administration – are in the process of drafting a joint set of guidelines to encourage the use of the open-source RISC-V ISA throughout China. Consequently, I’d expect to see WCH’s CH570 microcontroller used widely within China.
There are many obstacles – political and practical – that will make this microcontroller’s use outside of China more problematic. As stated in the previously referenced Reuters article:
“In 2023, Reuters reported that some U.S. lawmakers were putting pressure on the Biden administration to restrict American companies from working on the technology over concerns that Beijing was exploiting its open-source nature to advance its own semiconductor industry.”
Politically, things haven’t gotten any easier for Chinese semiconductor vendors since a new US government administration took over in early 2025.
There are the practical limitations as well. First, Chinese semiconductor companies tend to naturally emphasize Mandarin in their support ecosystem, not English. This is a natural tendency. I expect that the domestic Chinese market demand for these microcontrollers is going to be large in comparison to the demand in the rest of the world. You get a glimpse of that emphasis when you see that WCH encourages potential customers to buy its parts and development boards from AliExpress. There are few companies in the US that I am aware of that encourage the use of AliExpress as an approved component vendor. In truth, I could not find the WCH CH570 microcontroller or its development board when I checked AliExpress as I wrote this article.
Next, WCH generally refers people to Github for additional support software and code examples. I went to the Github page for WCH’s CH570 microcontroller and, well, the cupboard was bare when I checked. It may have been stocked since then. To be fair, I easily downloaded PDF manuals, written in excellent English, for both the WCH CH570 microcontroller and the QingKe RISC-V3 processor core family. However, the USB, 2.4GHz wireless, and Bluetooth cores used in the CH570 microcontroller are all proprietary WCH designs, so you will be dependent on WCH to develop and maintain the software drivers for these IP blocks. Ditto the development tools.
So, there you have it. Here’s an inexpensive and very capable microcontroller selling for a dime in some unknown quantity. Do you dare use it? The unit pricing is certainly attractive, but piecing together the development tools and finding a like-minded community of developers may prove a challenge, unless you’re based in China.
References
Che Pan and Brenda Goh, “Exclusive: China to publish policy to boost RISC-V chip use nationwide, sources say,” March 4, 2025.
Steve Leibson, “Fifty (or Sixty) Years of Processor Development…for This?,” EEJournal, March 29, 2018.
Steve Leibson, “RISC-V Aims for World Domination: Dr. David Patterson Foretells the Next Golden Age of Computer Architecture,” EEJournal, July 19, 2018.
Steve Leibson, “RISC-V Business: RISC-V Evolves from Academic Teaching Platform into a Major Microprocessor Player,” EEJournal, March 6, 2019.
Jean-Luc Aufranc, “10-cent WCH CH570/CH572 RISC-V MCU features 2.4GHz wireless, Bluetooth LE 5.0, USB 2.0,” CNX Software – Embedded Systems News, Markch 15, 2025.
Steve Leibson, A History of Early Microcontrollers, Part 1: Calculator Chips Came First
Steve Leibson, A History of Early Microcontrollers, Part 2: The Texas instruments TMS1000
Steve Leibson, A History of Early Microcontrollers, Part 3: The Rockwell Microelectronics PPS-4/1
Steve Leibson, A History of Early Microcontrollers, Part 4: The Intel 8048 and 8748
Steve Leibson, A History of Early Microcontrollers, Part 5: The Motorola 6801
Steve Leibson, A History of Early Microcontrollers, Part 6: The Fairchild F8 and Mostek MK3870
Steve Leibson, A History of Early Microcontrollers, Part 7: The Zilog Z8
Steve Leibson, A History of Early Microcontrollers, Part 8: The Intel 8051
Steve Leibson, A History of Early Microcontrollers, Part 9: The General Instruments PIC1650
You can always pick up an ESP32-C3 development board, which is RISC-V for <$5 in the US. It's supported by Tasmota off-the-shelf open source firmware as well, if you're not interested in Assembly programming.
The ESP32 offerings are truly low-cost products packed with capabilities.