Datasheet here: https://www.holtek.com/documents/10179/116711/HT68F001_0012v120.pdf https://www.holtek.com/documents/10179/116711/HT68F001_0012v... Notes: 1.

Datasheet here: https://www.holtek.com/documents/10179/116711/HT68F001_0012v120.pdf https://www.holtek.com/documents/10179/116711/HT68F001_0012v... Notes: 1. 512 12-bit words of Flash (12-bits per instruction). 2. Designed to be programmed directly in assembly. 3. 32kHz internal clock. When powered with 1.8V, the device is specified with 3.0 uA maximum current, and 1.5uA typical current. For reference, a 3000mA-hr AA battery with 15-year life span has ~22uA leakage current. 4. If that wasn't enough, the chip does have a "HALT" instruction, setting the processor into a sleep mode that further drops power consumption down. 5. All instructions require at least 4-clocks to execute. So this 32kHz CPU only executes 8 kilo-instructions per second... and some instructions require 2 cycles... meaning 4-kilo-instructions per second worst case. ---------- We programmers often forget how "small" the world of microcontrollers can get. Tiny chips, like this HT68F001 serve to remind us how small practical programs can be in the real world. Despite the hilariously poor specs of this uC (even by other uC standards), the power-consumption specs are absolutely spectacular. Its difficult for me to think of a rival chip that can dome down to 3uA worst-case specified current consumption at 1.8V. (A lot of the "low power uCs", like STM32U5, cheat by using a buck-converter and write their specifications against 3.3V). --------- By cutting clock speeds to the lowest reasonable speeds: these kinds of uCs allow the programmer to check on values thousands-of-times per second and react within microseconds to various events automatically. And they do so while using the absolute lowest amounts of power possible. That being said, communications will become an issue. An 8kHz uC without a UART will not even be able to communicate over 9600 Baud UARTs (aka: 9.6kHz communication speed), though bit-banging a signal out at 300 Baud might still be possible.