RPN scientific calculator firmware for $13 calculator kit

[Druzyek]

Quote:The diy kit uses an STC microcontroller...All you need to reprogram them is a USB to serial converter dongle thing.

I was looking at those this past week for my own DIY project. At least one of the models has a schematic showing how you can directly wire USB to two of the pins and program it with no dongle! They have some other cool stuff, but I passed on them since they don't support external program memory like traditional 8051s. The Atmel AT89LP51 costs about $2 in qty 1, also does single cycle execution, and supports external program and data memory, but it only runs at 20MHz vs 35MHz for some of the STC chips. Dallas has one that runs at 33MHz for $25 if you want all of those features. In any case, it's hard to beat an 8051 if you want to build a DIY calculator with a lot of memory and you're sticking to through hole microcontrollers.

Good luck on your project! I'm gonna buy one of the kits and I'd love to try out your firmware when you're finished.