The Acorn System 1 Monitor

"The System 1 Monitor is contained in two fusible link PROM's (74S571) is very easy to use and provides the following facilities using one of the 8154 devices as a keyboard interface and display driver:

Display indicates data transfer during loading and reverts to reset on successful completion.

The monitor provides a number of useful subroutines which can be inserted in user programs and includes a character font for seven segment representation of the complete ASCII character set.

The System 1 is provided with a Users Manual which includes an introduction to binary numbers, descriptions of the 6502 internal architecture and Acorn hardware, a listing and explanation of the instruction set and monitor program and a step by step introduction to machine code programming complemented by 16 original applications programs."

The Monitor program is only 512 bytes so if loaded into an EPROM there is space to spare, I have a build, for a 4K EPROM, which includes all the applications listed in the Acorn System 1 User Manual and Teletext Board Technical Manual with some other useful programs:

I have updated the applications, some fixes and extra programs, here is the original for those that already have it blown into an EPROM (e.g. Centre for Computing History's System 1 Trainers).

Note that the original System 1 User Manual was rife with errors so there is no guarantee that all the applications work correctly though I have fixed all the errors that I have found.

I have also created individual assembler listings for these applications and converted them to .wav format using a Python tool I've called bin2wav, they can then be 'played' from a PC straight into your System 1.


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