BBC Microcomputer Service Manual Oct 1985 Section 1 BBC Micro ...
BBC Microcomputer Service Manual Oct 1985 Section 1 BBC Micro ...
BBC Microcomputer Service Manual Oct 1985 Section 1 BBC Micro ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
1.2.3 Expansion<br />
The following expansion options are available, some of which may be<br />
fitted internally at purchase, but all of which could be fitted by<br />
Dealers at a later date:-<br />
* Floppy disc interface (fitted as an option at purchase)<br />
* Econet network interface (fitted as an option at purchase)<br />
* Voice synthesis circuit with cartridge ROM pack interface<br />
* Various alternative high-level languages in ROM<br />
External options which plug directly into the machine include:-<br />
* Games paddles<br />
* Cassette Recorder<br />
* Black and White and colour monitors and televisions<br />
* 5 1/4" disc drives, ranging from single-sided single density (100K)<br />
to dual double sided double track density (800K).<br />
* Dot-matrix or daisy wheel printers, serial or parallel interface<br />
* Teletext acquisition unit enabling Tele-software to be downloaded<br />
into the <strong>BBC</strong> Computer as well as providing access to the normal<br />
Teletext services. Pages may be "grabbed" and stored for later use.<br />
* 3 MHz 6502 second processor with 64K of RAM.<br />
* Z80 second processor with 64K of RAM and a fully CP/M-compatible<br />
operating system.<br />
* IEEE interface<br />
* Winchester 10 megabyte disc drive<br />
* Prestel adaptor unit<br />
1.2.4 Software<br />
Considerable attention has been paid to the overall design of both<br />
systems and applications software. A modular approach has been adopted<br />
specifically to ease the interfacing of various high-level languages (<br />
such as BASIC and Pascal) to the operating system.<br />
1.2.5 Machine Operating System<br />
A 16K ROM is used for the MOS. This software controls all input/output<br />
devices using a well defined interface. The MOS supports the following<br />
interrupts (the full implementation only being available from MOS 1.2<br />
onwards):-<br />
* Event Timer (10ms) (used as an elapsed time clock)<br />
* 4 channel analogue to digital converter<br />
* Vertical sync<br />
* Keyboard and keyboard buffer<br />
* Music tone generation and buffer<br />
* Serial interface, input and output buffers<br />
* Parallel input/output port<br />
and 'hooks' are provided to support other devices such as:-<br />
* Teletext acquisition<br />
* Prestel acquisition<br />
* Econet file system<br />
* Disk file system<br />
* Byte transfer to second processor<br />
The majority of the operating system calls are vectored to enable the<br />
user to change them if required.<br />
4