AIM-65

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AIM-65
AIM-65
Comelta Drac-1
Comelta Drac-1
Comelta Drac-1 and expansion box
Comelta Drac-1 and expansion box
back of expansion box
back of expansion box

The Rockwell AIM-65 computer was a development computer based on the MOS Technology 6502 microprocessor introduced in 1976. The AIM-65 was essentially an expanded KIM-1 computer. Available software included a monitor with line at a time assembler/disassembler, BASIC intepreter, assembler, Pascal, PL/65, and FORTH development system. Available hardware included a floppy disk controller and a backplane for expansion.

Standard software included the system console monitor software in ROM, called Advanced Interactive Monitor. It featured line assembler, disassembler, setting and viewing memory and registers, starting execution of other programs and more. Single stepping was made possible using non-maskable interrupt (NMI). The command prompt was the less-than sign "<", and on receiving a single character command, it added this input character and the greater-than sign ">". If the thermal printer was turned on, this would be output on a single line. The monitor included a number of service routines that could be accessed and used by a user's program to control I/O and code execution, and was fully documented, including source code.

The machine featured dual cassette tape control. This made it possible to write large assembly programs using the two pass assembler ROM. Source code in text was written twice consecutively to the input tape, and then the assembler, which could start/stop the input cassette tape using motor control was invoked. During the first pass the symbol table was built and stored in RAM. During the second pass symbols would be translated and code written out to the second tape, also using start/stop motor control. Being able to avoid storing code in RAM made it possible to save much space. It was however, still important to keep the symbols list short since RAM size was often no more than 4 KB.

In 1981 Rockwell introduced an improved model with a 40 character display as the AIM-65/40.

MTU made a "Visible Memory" card in 1978 that worked with the KIM-1 and AIM-65 computers, providing raster graphics display capability. MTU also made the first real time music synthesizer for a microcomputer; it worked with the KIM-1 and AIM-65, and featured a DAC with software providing 4 voices of wavetable synthesis.

At Spain they were distribuited by Comelta. This company made various card expansions:

  • CR-106 8 Kbytes of RAM
  • CR-119 RAM / ROM / PROM expansion
  • CR-120 Universal programming
  • CR-115 Microcassette controller(two units)
  • CR-113 Video controller
  • CR-401 Board Bus Extension(Standard S-64)

Comelta assembled all the options in a single box to produce a new computer, the Comelta Drac-1. The first prototype used microcassetes, but definitive versions have two 8" floppy disk drives.[1]

In 2003, some of these 27 year old computers were still in use controlling various displays and creatures at a high tech Halloween show near Alexandria, Virginia, U.S.A.

Contents

[edit] Technical specifications

  • Built in full sized QWERTY keyboard
  • 20 character alphanumeric LED display (16 segments)
  • Integrated 20 character thermal printer
  • RS-232 serial interface
  • Expansion connector
  • Application connector with 6522 VIA chip
  • 4 KB RAM
  • 5 sockets for 4 KB ROM/EPROM chips

[edit] Programming

PL/65 was a programming language designed and implemented by Rockwell International for the AIM-65.[2] It is based on a mix of ALGOL and PL/I, simplified where possible in order to adapt to the limited processing environment afforded by the 6502 (64k memory for instance).

[edit] References

  1. ^ http://cgi.ebay.es/ws/eBayISAPI.dll?ViewItem&item=180192737045 Ebay Auction of Drac-1 prototype
  2. ^ Manual for PL/65 (Text). Motorola 680x0 Resources. Retrieved on June 23, 2006.

[edit] External links