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Fulcrum   VIO-X Video Board

This was the first board Fulcrum made themselves.  Up until then they just resold IMSAI boards.
If anybody has a better image of this board please let me know.

Fullcrum Video Board

As I said in the Fulcrum History section, Fulcrum sold IMSAI boards -- amongst which was the IMSAI VIO video board. However that board was a simple memory mapped video board which suffered from screen glitches as the screen was being updated.  Fulcrum set about making their own non-memory mapped video board which is described here. 

The "VIO-X" Video I/O Interface as they called it, provided features equal to most intelligent terminals of the time both efficiently and economically. It allows the use of standard keyboards and CRT monitors in conjunction with existing hardware and software. It will operate with no additional overhead in S-100 systems regardless  of  processor  or  system  speed.

Through the use of an Intel 8275 CRT controller with an onboard 8085 processor and 4K of memory, the VIO-X interface operates independently of the host system and communicates via two ports, thus eliminating the need for host memory space. The screen display rate was effectively 80,000  baud.

There were two variations of the board.

The VIO-X1 provided an 80 character by 25 line format (24 lines plus status line) using a 5x7 character set in a 7x10 dot matrix to display the full upper and lower case ASCII alphanumeric 96 printable character set (including true descenders) with 32 special characters for escape and control characters. An optional 2732 character generator was available which allowed an alternate 7x10 contiguous graphics character  set.

The VIO-X2 also offered an 80 character by 25 line format but uses a 7x7 character set in a 9x10 dot matrix allowing high-resolution characters to be used. This model also included expanded firmware for block mode editing and light pen location. Contiguous graphics characters however were not supported.

Both models support a full set of control characters and escape sequences, including controls for video attributes, cursor location and positioning, cursor toggle, and scroll speed. An onĀ­board Real Time Clock (RTC) was displayed in the status line and could be read or set from the host system. A checksum test was performed on power-up on the firmware EPROM.

Video  attributes provided by the 8275 in the VIO-X  included:


The above functions could be toggled together or separately.  This was an excellent board. Comparables would for example be the SD Systems 8024, but none had the useful RTC option on the status line.

The manual for this board can be obtained here.


Other Fulcrum  S-100 Boards
64K Static RAM      256K Static RAM      VIO Video Board     Omnidisk FDC


This page was last modified on 10/25/2013