The Tektronix TDS 520 is a digitizing oscilloscope from the early 90s. It offers 500 MHz analog bandwidth, 500 MS/s sampling rate, 2 full-featured channels and 2 auxiliary channels with a limited vertical sensivity. Although being at age nowadays, this oscilloscope has perfect properties for a prominent place in the shack at home.
My TDS 520 was saved from the scrapheap.
When I wanted to gently interface an incremental rotary encoder with an 8-bit Atmel AVR microcontroller, I couldn’t find a nice example. That’s why I wrote this little text. Many other howtos, manuals and descriptions are fuzzy, incomplete or too complicated to do the (easy) job.
This article describes three things: the hardware (just the minimal hardware) and two pieces of code. The first is just a simple interrupt based program and the other uses timers to make bigger steps when you turn faster.
I use Atmel AVR studio as IDE and the Through hole USBprog to program the microcontroller.