BBC Micro

The British Broadcasting Corporation Microcomputer System is a microcomputer designed by Acorn Computers in the 1980s for the BBC Computer Literacy Project. BBC Micro is highly linked to ARM History.

In Italy it never appeared, but due to its importance we try to sketch here a bit.

The computer had an "education" orientation: in the last years its brand was revamped as a tool for Makers, with the BBC Micro.

General description

Hardware and costs

Based on MOS-6502 , the first two model was called Model A (16KB RAM) and Model B (32KB). The price seattled around £299 and £399 respectively. More than 1.5 million BBC Micros were sold but the production costs was higher then C/64 and ZX Spectrum

A 6502-based machine had memory running at twice the CPU speed. Then the video chip would be able to read the data while CPU was busy processing the data just read. This idea was used in the Apple and Commodore machines.

BBC micro instead let the 6502 run at 2Mhz, and accepted bus contention issues.

Graphic

BBC Micro supports 8 "modes", from 160 × 256 x 8 colors up to 640 × 256 x 2 colors. Some of this modes required up to 20Kb and cannot be used on Model A

Software

BBC BASIC was built in and offered:

• Structured control flow (REPEAT...UNTIL)
• Built-in assembler: see Chapter 4 on ARM Assembly Language Programming by Pete Cockerell for a deep dive on this feature. Other software could be installed via a ROM socket or tape

Legacy and importance

Acron produced a 32bit RISC computer during 1985, called ARM1 designed on a BBC Micro.