Rom/Ram Card For Electron Plus One

EE 48 February 1987 ROM/RAM CARD FOR ELECTRON PLUS ONE Here is a 32 Kbyte ROM and/or RAM extension module which plugs straight into the Plus One cartridge slot. In other words: extra memory for the baby brother of the BBC-B micro! Many programs available for the Acorn Electron microcom- puter come in the form of ROMs (read only memory chips) to go round the problem of having to load the program in the limited RAM space available. These ROMs either start up immedi- ately after power-on, or they can be accessed by means of a par- ticular user command. ROMs are generally classified as Ser- vice (S) ROMs, Language (L) ROMs, or a combination of these, S/L-ROMs. Although it would be beyond the scope of this article to ex- pound the intricacies of ROM filing, priority assignment, and identification strings, it is none the less useful to consider the memory organization of the Electron micro fitted with a Plus One extension. Fig. 1 shows that the address range from 8000h to BFFFh can be u...