The cheapest flash microcontroller you can buy is actually an Arm Cortex M0+ @jaydcarlson
Browse the Microcontroller pages of LCSC and you’ll see tons of low-cost MCUs from companies like Padauk, Nyquest, Holychip, SimOne, and Fremont Micro Devices — with prices as low as 4 cents.
The problem is these parts all use EPROM: Electronically Programmable Read Only Memory. The missing “E” means these aren’t electronically erasable — they’re OTP (One-Time Programmable) parts. Once you’ve burned your hex file, you’re locked in. OTP parts are widely used for simple devices in cost-sensitive applications, but they’re annoying to use in designs since to develop firmware, you need special emulator hardware (or a huge supply of ICs and a conveniently-located trash can).
Jay Carlson was interested in finding the cheapest flash microcontroller LCSC sells, and it turns out it’s not a crusty old 8051 or a PIC16 clone — and it’s not the WCH CH32V003 that the Internet is freaking out about — it’s actually an Arm Cortex-M0+ made by Puya, it’s less than 10 cents in moderate quantities, and it’s awesome.
Puya? They’re a flash memory company out of Shanghai that’s been around since 2012 — mostly making really low-cost SPI flash memory for IoT gadgets. While it may seem odd that the cheapest MCU is made by a Flash memory company, if you know a thing or two about chip design (which I don’t) you’ll know that it’s often the flash memory inside the part that’s the most expensive IP in the design. This is why so many fabless semiconductor shops don’t bother with it and just use external SPI flash or OTP memory (just look at any USB webcam controller, Bluetooth audio chip, or even the popular Espressif products).
Jay looks at the Puya PY32 line and compares to the CH32V003 and STM32F030.
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