Inspired through the famous article by Don Lancaster, about a tiny self-made display, attached to an ASCII Keyboard (Popular Electronics, issue April 1974). It displays the character on a 5x7 dot matrix display. The binary row address is shown by LEDs and you can see how the display is being built up by stepping through the 7 horizontal scan lines. The clock speed can be adjusted from 0.6 Hz to 800 Hz.

Connect an Apple-1 or Apple ][ keyboard directly using the DIP-16 connectors, or use the ASCII Data In pins. Verify the ASCII input to the character generator using the character address LEDs. A power supply with +5V and -12V is needed as a minimum. The -5V is regulated on the board itself. Provide +12V when this voltage is needed by the attached keyboard. Supported character generators: Signetics 2513, 2316B, 2716 EPROMs and 2816 EEPROMs. Extra, feed the 8-bit counter output to the ASCII Keyboard Tester!