Vectron 65 Plus

The Vectron 65 Plus is a 6502 CPU-based computer with keyboard support that can run BASIC. It is highly extensible via 32 GPIO pins.

At present, I have built the following peripherals for the computer:

• Vectron VGA Plus v2 - VGA output with pixel-level control
• Vectron VGA Plus Text Mode - Add-on for Vectron VGA Plus v2 that simplifies displaying text on screen
• Vectron Sound Plus - Audio output with the AY-3-8910 sound generator chip

Read on for demonstrations of each of these add-ons.

This is an enhanced version of my Vectron 65 computer.

How It Works

At the heart of the system is a WDC 65C02 CPU running at 8 MHz. 32 KB of SRAM is available, and a 32 KB ROM chip stores the program to execute (you can burn the ROM with my Arduino code). A pair of 6522 VIA chips add a total of 32 GPIO pins to interface with external peripherals. A PS/2 connector is present to support a keyboard (or a mouse, in theory, though I haven't tried one yet) — the clock and data lines are routed to GPIO pins.

This is the circuit design:

Media

Here, the Vectron 65 Plus (left) is running TinyBASIC. On the right, Vectron VGA Plus Text Mode is stacked on top of Vectron VGA Plus v2 to provide a text mode VGA display output (6502 code here):

In this example, the Vectron 65 Plus (right) is hooked up to Vectron VGA Plus v2 to output some bitmap graphics (6502 code here):

And for audio, I added in the Vectron Sound Plus module:

You can download an MP3 here of a tune I made with it.

And a few more pictures:

Bill of Materials

• 1 x 65C02 CPU
• 2 x 6522 VIA
• 1 x 28C256 ROM
• 1 x AS6C62256A RAM
• 4 x 74682
• 1 x 7404
• 1 x 7408
• 1 x 7432
• 1 x 8 MHz crystal oscillator
• 1 x push button
• 4 x 3.3K resistors
• 2 x 5.1K resistors
• 2 x 10K resistors
• 3 x 47 uF electrolytic capacitors
• 14 x 0.1 uF ceramic capacitors
• 1 x PS/2 connector
• 1 x PCB (Kicad design file here)

About the Author

Nick A. Bild, MS