MOV is Turing-Complete: 4-bit Adder Implementation

In late 2017, small groups of our class were given the task to delve into the assembly language and write a program for the 8051 microcontroller, as part of the Low-Level Programming lecture. This post documents the project MOV is Turing-Complete: 4-bit Adder Implementation — an assembly program that adds two 4-bit numbers relying solely on mov instructions. The appendix lists the minified version of the code. Continue reading MOV is Turing-Complete: 4-bit Adder Implementation

ShiftRegister PWM Library

The ShiftRegister PWM Library enables usage of shift register pins as pulse-width modulated (PWM) pins. Instead of setting them to either high or low, the library lets the user set them to up to 256 PWM-levels. This post serves as a documentation page for the library and is to be extended over time. Continue reading ShiftRegister PWM Library

Port Manipulation and Arduino’s digitalWrite Performance

The widely used Arduino IDE offers many easy-to-use functions, one of them is  void digitalWrite(uint8_t pin, uint8_t val) . It sets one of the microcontroller’s pins to either high or low and serves well in many cases. However, it has a really poor performance, i.e. execution time. This post analyses both, speed and interior of the digitalWrite function, and proposes alternative, high performance solutions for setting output pins.
Continue reading Port Manipulation and Arduino’s digitalWrite Performance