The Screenware software automatically converted the coordinates into the card's coordinates. MicroAngelo also supported a light pen, connected through input terminals on the top of the card.
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. The MA520 also used 64 kB DRAMs and 2732 EPROMs to reduce chip counts and expand the frame buffer to 64 kB. The MA520 locked down only the two ports it actually used. 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. 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. The MA512 had a number of problems that were addressed in the later MA520, released in 1982. 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 optional 6 kB "Screenware Pak II" (in 8 kB of ROM) was a superset of Pak I, adding circle, line and polygon drawing routines, flood fill and a variety of other features. The 4 kB ROM normally contained "Screenware Pak I", which provided routines to emulate an 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 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 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. Users programmed the MicroAngelo in assembly language using the Z80's input/output parallel ports, which sent data over the internal S-100 bus at relatively high speeds. 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. Early versions of AutoCAD supported the MicroAngelo system. 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). Each MicroAngelo board produced a 512 by 480 pixel monochrome image, high resolution for the era. SCION's MicroAngelo was an early graphics card for S-100 bus computers. Not to be confused with Microangelo Toolset.