Variations of the Mod 8-4 ROM Board
C-MOD 8-4 2K PROM
Celetron created its own version of the Mod 8-4 designated the C-Mod 8-4. The C-MOD board was addressable to any segment in a 64K memory system (unlike the original boards which were addressable to any segment within the first 16K). In addition, since most 1702s didn't have the access time needed to run with many "modern" CPUs at the time, a one-shot is provided on the board to provide a not-READY signal to the CPU system for an appropriate time period. This feature was not present on the original MOD 8-4 board.
MAC 88-104-10 ROM Board (TSL)
Nothing is known about this board other than the name. If you have anything on the company TSL, please let me know. I suspect it is a local (Toronto) company. Note these boards have a small Space Circuits logo on them.
Celetron created its own version of the Mod 8-4 designated the C-Mod 8-4. The C-MOD board was addressable to any segment in a 64K memory system (unlike the original boards which were addressable to any segment within the first 16K). In addition, since most 1702s didn't have the access time needed to run with many "modern" CPUs at the time, a one-shot is provided on the board to provide a not-READY signal to the CPU system for an appropriate time period. This feature was not present on the original MOD 8-4 board.
MAC 88-104-10 ROM Board (TSL)
Nothing is known about this board other than the name. If you have anything on the company TSL, please let me know. I suspect it is a local (Toronto) company. Note these boards have a small Space Circuits logo on them.
Mod 8-4 ROM Board (Space Circuits)
This is the standard board made by Space Circuits. Modified by the user so that the starting address is 304 000.
MAC 88-104-10 ROM Board (TSL) - Modified address 360 000
TSL MAC 88-104-10 ROM Board. Modified by the user so that the starting address is 360 000. It contains ROMs 0-7 of Processor Technology's "Software Package #1".
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MAC 88-104-10 ROM Board (TSL)
Un-modified TSL MAC 88-104-10 ROM Board. This appears to be the same as the Space Circuits board except for the logo, number and the slight difference in the shape of the board itself. There is a small Space Circuits logo in the top RH corner.
MAC 88-104-10 ROM Board (TSL) - Modified address 370 000
TSL MAC 88-104-10 ROM Board. Modified by the user so that the starting address is 370 000. It contains ROMs 8-13 of Processor Technology's "Software Package #1".
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The Processor Technology's "Software Package #1" is described as a self-contained program development system (i.e., assembly language operating system) made for 8080 based computers. Included in the package was an executive to handle memory files, an assembler, and a line-oriented editor.
Processor Technology supplied free copies on cassette to bona fide amateur computer clubs, thus making this software widely available. According to the manual, they provided the software free, because they it would lead to increased 8k RAM board sales, which would be required to develop any reasonably sized programs with the software.
At some point, someone converted this software to work on the Mod-80, which is what is on the 14 EPROMs above.
Processor Technology supplied free copies on cassette to bona fide amateur computer clubs, thus making this software widely available. According to the manual, they provided the software free, because they it would lead to increased 8k RAM board sales, which would be required to develop any reasonably sized programs with the software.
At some point, someone converted this software to work on the Mod-80, which is what is on the 14 EPROMs above.
Last updated on March 15, 2019.