VintageCalc - A delay-line memory calculator on an FPGA

The interface board – cheap and discrete ;-)

Counter-clockwise from the top, we have the stroke generators (transistor/capacitor), the two weighted resistor DACs, the beeper, the keyboard matrix connector, and the XYZ outputs.

The vector drawn display, shown on a Leader 1041 oscilloscope.

In XY mode, I had to use x10 magnification and DC coupling for reasonable X linearity, and channel 2 invert for correct Y orientation. Note sign indicator, decimal point, and the subtly centred one digits.