• Another update on the CNC.

    The interfaceboards are etched, soldered and tested.

    IO / Control Boards

    IO / Control Boards

    Step- and directionsignals are generated by an ATmega32 which is controlled over RS232.
    This is only for testing purpose. In the final version a PC will control the movement.

    Tags: , , , ,

  • R/2R Digital to Analog Converter

    R/2R Digital to Analog Converter

    The first thing I wanted to do with the new oscilloscope was to test the X-Y-Mode. Not with some lame Lissajous-figures but with arbitrarily adjustable positions. And the easiest way to to so, was to take an ATMega32 and two DAC’s.

    I had two parallel-input DAC’s lying around, but i did not want to make a layout or to wire so many pins.
    The next best alternative was to build two R/2R-resistor ladders. I found a large amount of 620kΩ resistors (can’t remember why I bought them. They seem to have been there for years.) and some perfboard.

    I wired the resistor networks directly to Port A and B of the AVR, so I could directly assign 8-bit numbers to the port register. I wrote a simple program where an interrupt updates the ports at ca. 30Hz and displays some bouncing dots.

    Tags: , , , , ,