[kragen]

That's out of stock, though. Here are my other shockingly inexpensive MCUs at LCSC that were in stock at the time:

links from 02025-03-16:

https://www.lcsc.com/product-detail/Microcontrollers-MCU-MPU... #LCSC #pricing for 16-pin #CH32V003 #microcontrollers #electronics #hardware: 14.21¢ in quantity 500. Not the cheapest, but it’s a RISC-V with IIRC an on-board op-amp, though the linked datasheet only covers the CPU really.

https://www.lcsc.com/product-detail/Microcontrollers-MCU-MPU... #LCSC #pricing for 14-pin #PY32 #ARM #microcontrollers #hardware, 9.01¢ in quantity 500. Not the cheapest, but it’s an ARM. #electronics

links from 02025-02-08:

https://www.lcsc.com/datasheet/lcsc_datasheet_2410121502_PAD... #PDF English #datasheet for #Padauk PFS122 #microcontrollers which have a 12-bit ADC and 24MHz. Not quite the cheapest microcontroller but they only cost 4.32¢ in quantity 2000.

links from 02024-08-01:

https://www.lcsc.com/product-detail/Microcontrollers-MCU-MPU... new cheapest #microcontrollers: Cypress CY8C4045FNI-DS400T, 1.5¢ in quantity 1000. It purports to be a 48MHz Cortex-M0 ARM with 32KiB of Flash and 4KiB of SRAM in a 1.6mm x 2mm package, 0.31-0.37 mm thick, with nine GPIO pins. I think that’s 4000 Dhrystone MIPS per dollar. #electronics #hardware #pricing

links from 02024-05-12:

https://jlcpcb.com/partdetail/NyquestTech-NY8A051H/C5143390 #JLCPCB has new cheapest #microcontrollers: #Nyquest NY8A051H: 1.58¢ each in quantity 20000, or 3.2¢ in quantity 1 #hardware #pricing

links from 02023-10-12:

https://www.lcsc.com/product-detail/Microcontroller-Units-MC... #Padauk PMC251 is one of their cheapest multithreaded parts; LCSC lists it here at US$0.1071 in quantity 500, which works out to US$53.55. 1 kiloword instruction memory

As of today (02025-10-15), the CH32V003A4M6, the PY32F002BD15S6TU, the PFS122, and the PMC251-S14 are in stock. The CY8C4045FNI-DS400T, the CY8C4013SXI-400, and the NY8A051H (not an 8051 despite the name) are out of stock. Today what I see are:

https://www.lcsc.com/product-detail/C49173938.html Currently cheapest #microcontrollers #pricing on LCSC: PMS150G-U06 (a SOT-23-6) for 2.02¢ in quantity 3000. #Padauk has broken the 3¢ barrier! One-time programmable. #electronics #hardware

https://www.lcsc.com/product-detail/C2857167.html Almost cheapest #microcontrollers #pricing on LCSC: NY8A054ES8, a SOP-8, for 3.91¢ in quantity 1000. This is from JSMSEMI (Shenzhen JSMicro Semiconductor Co., Ltd.) 1T 8-bit 8MHz chip, 128 bytes RAM, 2k × 14-bit EPROM program memory (but no quartz window, so one-time programmable). 8-level hardware stack. The datasheet is full of descriptions of peripheral registers and pin circuit schematics, and then the 55-instruction instruction set is documented on pp. 76–91.

[SuperMouse]

The Padauk and Nyquest are barely useable. They are highly specialized devices (often ROM-only).

Cheapest "general purpose" microcontrollers that have enough features for good developer experience are Puya and WCH.

If you are a seasoned STM32 developer you will get used to them within a day.

Examples:

https://download.py32.org/Datasheet/en/PY32F071_Datasheet_Re...

https://arvidtek.com/wp-content/uploads/2025/06/CH32V006DS0-...

[kragen]

While I mostly agree, I have some small quibbles which I think will present a more complete picture.

I've had a good developer experience with 74LS00-family SSI chips (like the quad-NAND-gate 74LS00 and the hex-inverter 74LS04), so your mileage may vary.

Just to clarify, the Padauk and Nyquest chips I linked above are one-time programmable (PROM), not mask ROM, except the PFS122 (3.53¢), which is reprogrammable Flash. (It's advisable to debug your code with a Flash chip or an ICE before you start consuming PROM chips, unless you really like to desolder.) Padauk doesn't seem to make mask-ROM chips at all, and I haven't seen any from Nyquest.

I'm not sure what you mean by "highly specialized". They're tiny, slow 8-bit microcontrollers, so you will certainly be disappointed if you go in hoping for STM32-like capabilities. But they're programmable, and their peripherals don't include things like LiDAR pulse timing circuits or AES encryption hardware or anything like that. It's just very general-purpose stuff like watchdog timers and PWM generators.