Ascii Video terminal

Design by Geoff Graham in the magazine Silicon Chip, 2014

I have the kit as sold by Silicon Chip, and recently bought the assembled version at Budgetronics.

All technical information, like circuit diagram, sources, documentation are available at Geoff Graham’ website.

ASCII VT100 compatible video terminal Already buid on PCB and ready for use.
Ideal interface to connect your microcontroller with a VGA monitor (or a composite videomonitor), standard PS2 keyboard and USB.


    • Single chip ASCII video display terminal with VT100 and VT52 emulation
    • VGA or Composite Video output with automatic switch over. Composite can be PAL or NTSC
    • VGA can display 24 lines x 80 characters or an extended resolution of 36 lines x 80 characters
    • Composite video can display 18 lines x 48 characters (PAL) or 15 lines x 44 characters (NTSC)
    • Standard PS2 compatible keyboard input with support for standard US keyboard layout or French, German, Italian, Belgian, Russian or United Kingdom keyboard layouts
    • TTL or RS232 serial input/output. Baud rates from 40 to 1,000,000 bits per second with odd, even or no parity and one or two stop bits
    • USB input with serial emulation. This can be used as a USB to serial converter
    • Extended VT100 terminal emulation. Extensions include graphics codes for drawing lines, boxes and circles (which can be hollow or filled)
    • Graphics resolution is 480×288 pixels in VGA 25 line mode, 480×432 pixels in VGA 36 line mode, 288×216 in PAL composite and 264×180 pixels in NTSC composite mode
    • Three built in fonts (standard, large and jumbo) and four character attributes (normal, underline, reverse and invisible)
    • Power requirement is 5V at 50mA plus any current drawn from the 3.3V pin on the serial connector, USB power supply

It works well for me. Nice crisp picture on my VGA terminals. Easy to use and configure, versatile as VT100 or VT52 with some extensions.