Acorn Electron

The Acorn Electron is a budget version of the BBC Micro educational/home computer made by Acorn Computers Ltd. It has 32 kilobytes of RAM, and its ROM includes BBC BASIC v2 along with its operating system.

The Electron was able to save and load programs onto audio cassette via a supplied converter cable that connected it to any standard tape recorder that had the correct sockets. It was capable of basic graphics, and could display onto either a television set, a colour (RGB) monitor or a "green screen" monitor.

At its peak, the Electron was the third best selling micro in the United Kingdom, and total lifetime game sales for the Electron exceeded those of the BBC Micro.

The hardware of the BBC Micro was emulated by a single customized ULA chip designed by Acorn in conjunction with Ferranti. It had feature limitations such as being unable to output more than one channel of sound, (and provided fewer Envelope-shaping options) where the BBC was capable of three-way polyphony (plus one noise channel) and the inability to provide teletext mode. Unlike the BBC Micro, the Edge-connector on the rear of the machine exposed almost all the Bus lines, but not all. (via the total number of ports that the BBC Micro had, it exposed all lines)

For Issue 1-4 motherboards, the ULA had an issue similar to those experienced by other socketed CPU's; Over time, the thermal heating and cooling could cause the ULA to rise slightly out of its socket just enough to cause the machine to start exhibiting 'hanging' or other startup-failure issues, such as a continuous 'startup beep'. This was despite a metal cover, and locking-bar mechanism designed to prevent this from occurring. Pushing down on the metal cover to reseat the ULA was normally sufficient to rectify these issues. Issue 5 and 6 boards utilized a different epoxy resin covering directly over the ULA, which resolved this issue.

The keyboard included a form of Single- key keyword input, similar to that used on the Sinclair Spectrum, via the 'func' key. However, unlike the Spectrum, the single-keypress keyword-entry was optional, and keywords could be entered manually if preferred.

The ULA controlled memory access and was able to provide 32K × 8 bits of addressable RAM using 4 × 64K × 1-bit RAM chips (4164). Due to needing two accesses to each chip instead of one, and the complications of the video hardware also needing access, reading or writing RAM was much slower than on the BBC Micro. This meant that although ROM applications ran at the same speed, there was a substantial speed decrease on applications running from RAM.