As a follow-up on the "MCU for a trivial task? Overkill?" I wrote a short note on some really really low cost MCU's.
Recently David L. Jones from EEVBlog (eevblog.com) has had a few blog entries and videos regarding som very low cost 8-bit MCUs from a Taiwanese manufacture named Padauk (www.padauk.com.tw). They are OTP, but on the other hand in reels of 3000 the cost is under 0.03 USD each, yes under 3 cents.
Here are the blog entries from David. EEVBlog is on it self a must on your Youtube subscriptions.
This has stirred up some large interest and as always the Open Source and Maker community is making a move. I would not be surprised if this follows the same events as what pushed Espressif Systems to world fame for their very low cost WiFi chip ESP 8266. The same with Allwinner, another Chinese semiconductor manufacture that recently has gained fame.
Padauk has a few series of MCUs. The F-series and the M-series are your basic MCUs. BLDC is a series with support for driving single or 3-phase BLDC motors. Finally the MCS is a, sort of, 8 core MCU.
Padauk calls its processor cores FPPA (Enhanced Field Programmable Processor Array). They actually trademarked this.
The difference between the F and M series is the memory type. F-serie has OTP memory, and is thus only one-time programmable. M-series has Padauk's own MTP memory, which stance for MULTIPLE programable memory.
Apart from this the processors contain the ordinary flavour of timers, PWM, comparators, clocks, and IO pins.
The MCUs are available in the usual packages such as DIP, SO and DFN/QFN.
One of the problems Espressif had in the beginning was lack of documentation in English. Padauk seams to have learned from that and has released some really decent data sheets, application notes and other documentation.
They also have a rather complete IDE that supports assembler as well as Padauks own "mini-C". A variant of C aimed at these very small MCU's with rather limited memory and RAM.
There is also a programmer available as well as a hardware emulator. Both for around 50-100 USD.
There are a number of places where you can buy Padauk's MCUs and their other products. One of them is LCSC (lcsc.com) in China.
Padauk has not released any in-circuit programming protocol nor any information around the programming what so ever.The available programmer is Padauks own. It works well and is fully integrated into the IDE.
In production this programmer is of course not a viable option. For a 3-5 cent processor there needs to be a much more efficient process. Luckily there is a solution for this. As with other manufacturers like Microchip, you can have these chips factory programmed. In the Padauk case for as low as 0.2 cents each.
So for 3-5 cents you can have a relatively advanced IO expander. Interesting development indeed.