Playing Chiptunes on the Ultra-Cheap Padauk PMS150c Microcontroller
Tobias Girstmair used the famously-cheap Padauk PMS150c microcontroller to build the most affordable chiptunes player imaginable.
There are, quite literally, hundreds of microcontrollers on the market today. We usually only get excited about the models that are powerful or that offer interesting new features. But sometimes you want to go the complete opposite direction and use a microcontroller that is dirt cheap — usually with the added benefit of being low-power. Of those, the ATtiny line is the most well-known. But there are many others, including the Padauk PMS150c microcontroller that costs a mere 3 cents per unit. Tobias Girstmair used the Padauk PMS150c to build the most affordable chiptunes player imaginable.
The Padauk PMS150c isn't a replacement for an STM32 or even an ATtiny85, because it has ludicrously conservative specs and only six IO pins. It also doesn't have reprogrammable flash memory, which means that you can only program it once. But it also only costs 3 cents, which makes it one of the cheapest microcontrollers on the planet. And, importantly for this project, it can produce PWM (Pulse-Width Modulation) signals using an 8-bit timer. It is possible to use PWM as a poor man's DAC (Digital-to-Analog Converter), which is useful for generating an audio signal. Girstmair previously built a chiptunes player based on an ATtiny4 and ported that project to work with the Padauk PMS150c.
Fortunately for Girstmair, enthusiasts in the community developed an open source C toolchain for the Padauk PMS150c. But that still requires its own instructions. The Padauk PMS150c is also far less powerful than the ATtiny4 — it only has enough program ROM for 1024 words and has just 64 bytes (not kilobytes or megabytes) of RAM. Despite those limitations, Girstmair was able to port his code to the Padauk PMS150c. He then crammed the microcontroller inside of an RCA jack with a tiny coin cell battery, so it can play music without any external components or connections. This is a very impressive accomplishment and we are amazed at what Girstmair was able to achieve with such a basic microcontroller.