Z80-Based Vector Graphic Single-Board Computer

Z80-Based Vector Graphic Single-Board Computer


Category: Uncategorized

Created: November 28, 2008

Updated: January 27, 2020

Language: VHDL

Other project properties

Development Status: Alpha

WishBone compliant: Yes

WishBone version: n/a

License: LGPL


An implementation of the Vector Graphic, Inc. Computer System of the early 1980's on a Xilinx Spartan 3E Starter Kit. The Vector ZCB and FlashWriter II video card are implemented. The system also includes a memory management unit, serial ports, and keyboard interface. This design is based on several cores from OPENCORES.ORG. You can see some pictures of it running on my blog.


- Vector ZCB CPU Card - Uses OpenCores Wishbone High-Performance Z80 CPU Core - Can optionally use the OpenCores TV80 CPU Core if the wb_tv80 Wishbone wrapper is used. - Vector Graphic MON4.3 monitor stored in block RAM. - Two UARTs (Compatible with Vector Monitor) - PS/2 Keyboard interface to emulate the original parallel ASCII keyboard. - Flashwriter II Video Card - Uses OpenCores Monochrome Text-Mode VGA Video Display Adapter with custom Wishbone wrapper and original fonts from the Vector Graphic Flashwriter II. Display size changed to 80x24 to match the Flashwriter II. - Vector HD/FD Disk Controller - Uses StrataFLASH on Spartan 3E Board for storage. - Read-Only - Other - Memory Management Unit - Uses OpenCores Asynchronous DDR SDRAM controller - Wishbone backplane created using a modified version of OpenCores WISHBONE Builder


- Dec 15, 2008 Update
- Made UARTs compatible with Bitstreamer Card
- Can select either Mon 4.0C (serial) or Mon 4.3 (Flashwriter2) Monitor.
- Can boot CP/M using Mon 4.0C. this allows logging of console output.
- Fixed shifted keys bug in ASCII Keyboard. CTRL and Arrow keys not working.
- Fixed first character of each line corruption in Flashwriter2.
- Dec 7, 2008 Update
- Can boot CP/M 2.2 from Vector HD-FD controller.
- Ran exz80all.com instruction set exerciser. Some test failures.
- DDR Controller commented out, replaced with block RAM where possible:
- New memory map: 0-2FFF, B000-FFFFh RAM, enough for CP/M with 12K TPA.
- Running CP/M Exposes some PS/2 Keyboard bugs with shifted and CTRL characters.
- Tested on Spartan 3E Starter Kit
- Z80 Core, MMU, Flashwriter II, keyboard interface, UART working
- DDR SDRAM Controller has problems in this design and needs debugging. The RAM data retention seems fine, but I think the cache has an issue. The memr.com program can be run under CP/M to provide a thorough memory test.
- Can run the Vector Monitor 4.3 (Flashwriter for I/O) and Monitor 4.0C (Serial I/O)