MicroAngelo
Encyclopedia
SCION's MicroAngelo was an early graphics card for S-100 bus
computers. Each MicroAngelo board produced a 512 by 480 pixel monochrome image, high resolution for the era.Most home computers of the era displayed 256 to 320 by 192 to 240, while the Cromemco Dazzler
for S-100 machines produced only 128 by 128. The MicroAngelo Palette (or Colour Mixing) Card used the output of multiple MicroAngelo's as individual bit-planes to produce images with up to 256 colors (using 8 cards). Early versions of AutoCAD
supported the MicroAngelo system.
The original MA512 board included 32 kB of RAM
for the frame buffer, a Z80 processor operating as a controller and memory refresh driver, and 4 kB of ROM
containing one of two optional sets of subroutines. Users programed the MicroAngelo in assembler language using the Z80's input/output parallel ports, which sent data over the internal S-100 bus at relatively high speeds. The data sent over the bus was examined by the Z80 on the card, which then ran a selected subroutine contained in its ROM to place data into the frame buffer. The screen buffer could be moved to or from the computer's main memory - useful for printing when pushed from the card to the computer, or displaying bitmap graphics when reversed.
The 4 kB ROM normally contained "Screenware Pak I", which provided routines to emulate a 85 by 40 line character screen, which also allowed the user to define their own 12 by 6 pixel character sets in the card's RAM. The optional 8 kB "Screenware Pak II" was a superset of Pak I, adding circle, line and polygon drawing routines, flood fill and a variety of other features. Pak II also added a "split screen" function, allowing a portion of the screen to be placed in graphics mode and the rest in text mode, which some considered a necessity.
The MA512 had a number of problems that were addressed in the later MA520, released in 1982. In particular, the software interface required only two of the input/output "ports", but a single MA512 would lock down an entire set of eight, typically F0 to FF. This made expanding a system with a complete set of eight MicroAngelo boards difficult, because the eight cards and the associated palette card would end up using up the vast majority of 256 available ports. The MA520 locked down only the two ports it actually used. The MA520 also used 64 kB DRAMs and 2732 EPROMs to reduce chip counts and expand the frame buffer to 64 kB. Although the video system could only see one bank of 32 kB, the other 32 kB could be used for a variety of purposes, including scratch buffers and storing routines.
MicroAngelo also supported a light pen
, connected through input terminals on the top of the card. The Screenware software automatically converted the coordinates into the card's coordinates. Screenware also included routines for drawing movable cursors in hardware (as opposed to bit blit
ing), and the cursor could be made to follow the light pen simply by reading the pen coordinates and feeding them into the cursor.
Shortly after the MA520 was announced, SCION stated they were going to produce a standalone terminal consisting of a complete Zilog Z80
-based CP/M
machine packaged with a MA520, and optionally a monitor as well. Known as the Mirage 1, a version with a color monitor (and Palette Card) would be known as the Mirage 2. However, there is no record of either version having shipped.
Form and Function packaged a graphics terminal using a single MicroAngelo board placed inside an existing Ball monochrome monitor to produce the "IM-1". The IM-4 connected to any computer using a serial port
, data being passed along to the cards. The system could be upgraded to greyscale by adding additional cards, and to color by swapping the screen. This solution had a number of problems, including the fact that it did not support existing terminal standards like VT52
, and that the serial port
would start to bog down above about 6000 bps, slow even for the era.
S-100 bus
The S-100 bus or Altair bus, IEEE696-1983 , was an early computer bus designed in 1974 as a part of the Altair 8800, generally considered today to be the first personal computer...
computers. Each MicroAngelo board produced a 512 by 480 pixel monochrome image, high resolution for the era.Most home computers of the era displayed 256 to 320 by 192 to 240, while the Cromemco Dazzler
Cromemco Dazzler
Cromemco's Dazzler was a graphics card for S-100 bus computers. Released in 1976, it is the first commercial graphics card available for microcomputers. Multiple Dazzler cards could be installed in a single machine and synched together, a feature which could, with minor modification, be used to...
for S-100 machines produced only 128 by 128. The MicroAngelo Palette (or Colour Mixing) Card used the output of multiple MicroAngelo's as individual bit-planes to produce images with up to 256 colors (using 8 cards). Early versions of AutoCAD
AutoCAD
AutoCAD is a software application for computer-aided design and drafting in both 2D and 3D. It is developed and sold by Autodesk, Inc. First released in December 1982, AutoCAD was one of the first CAD programs to run on personal computers, notably the IBM PC...
supported the MicroAngelo system.
The original MA512 board included 32 kB of RAM
Ram
-Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...
for the frame buffer, a Z80 processor operating as a controller and memory refresh driver, and 4 kB of ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
containing one of two optional sets of subroutines. Users programed the MicroAngelo in assembler language using the Z80's input/output parallel ports, which sent data over the internal S-100 bus at relatively high speeds. The data sent over the bus was examined by the Z80 on the card, which then ran a selected subroutine contained in its ROM to place data into the frame buffer. The screen buffer could be moved to or from the computer's main memory - useful for printing when pushed from the card to the computer, or displaying bitmap graphics when reversed.
The 4 kB ROM normally contained "Screenware Pak I", which provided routines to emulate a 85 by 40 line character screen, which also allowed the user to define their own 12 by 6 pixel character sets in the card's RAM. The optional 8 kB "Screenware Pak II" was a superset of Pak I, adding circle, line and polygon drawing routines, flood fill and a variety of other features. Pak II also added a "split screen" function, allowing a portion of the screen to be placed in graphics mode and the rest in text mode, which some considered a necessity.
The MA512 had a number of problems that were addressed in the later MA520, released in 1982. In particular, the software interface required only two of the input/output "ports", but a single MA512 would lock down an entire set of eight, typically F0 to FF. This made expanding a system with a complete set of eight MicroAngelo boards difficult, because the eight cards and the associated palette card would end up using up the vast majority of 256 available ports. The MA520 locked down only the two ports it actually used. The MA520 also used 64 kB DRAMs and 2732 EPROMs to reduce chip counts and expand the frame buffer to 64 kB. Although the video system could only see one bank of 32 kB, the other 32 kB could be used for a variety of purposes, including scratch buffers and storing routines.
MicroAngelo also supported a light pen
Light pen
A light pen is a computer input device in the form of a light-sensitive wand used in conjunction with a computer's CRT TV set or monitor. It allows the user to point to displayed objects, or draw on the screen, in a similar way to a touch screen but with greater positional accuracy...
, connected through input terminals on the top of the card. The Screenware software automatically converted the coordinates into the card's coordinates. Screenware also included routines for drawing movable cursors in hardware (as opposed to bit blit
Bit blit
Bit BLIT is a computer graphics operation in which several bitmaps are combined into one using a raster operator....
ing), and the cursor could be made to follow the light pen simply by reading the pen coordinates and feeding them into the cursor.
Shortly after the MA520 was announced, SCION stated they were going to produce a standalone terminal consisting of a complete Zilog Z80
Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...
-based CP/M
CP/M
CP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
machine packaged with a MA520, and optionally a monitor as well. Known as the Mirage 1, a version with a color monitor (and Palette Card) would be known as the Mirage 2. However, there is no record of either version having shipped.
Form and Function packaged a graphics terminal using a single MicroAngelo board placed inside an existing Ball monochrome monitor to produce the "IM-1". The IM-4 connected to any computer using a serial port
Serial port
In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time...
, data being passed along to the cards. The system could be upgraded to greyscale by adding additional cards, and to color by swapping the screen. This solution had a number of problems, including the fact that it did not support existing terminal standards like VT52
VT52
The VT52 was a CRT-based computer terminal produced by Digital Equipment Corporation introduced in September, 1975 . It provided a screen of 24 rows and 80 columns of text and supported all 95 ASCII characters as well as 32 graphics characters. It supported asynchronous communication at baud rates...
, and that the serial port
Serial port
In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time...
would start to bog down above about 6000 bps, slow even for the era.