Some people think that programs for microcontrollers like the 8051 that have limited program memory must be written in assembly language rather than a high-level language like C. The executable code ...

A while back, [Matt] bought a few 8051 MCUs and tucked them away for a future project. He just found these fabulous little chips in a component drawer and decided it was time to figure these guys out.

Although 8051-compatible microcontrollers with SPI ports are available, a lower-cost device with an SPI port bit-banged through GPIO pins often suffices. The code shown here takes advantage of ...