EPROMS FOR SPECTRUMS
EPROM SERVICES has produced a Spectrum version of its EPROM board for the 16K Spectrum. It is in the top 8K of memory from 56K to 64K which is normally empty. It consists of four sockets on a board, to which can be added static RAMs - 6116 type - or 2K EPROMs - 2716 +5V type.
As yet there are no EPROMs available for the Spectrum but some will soon be available.
EPROM 1 contains 10 small routines for program editing such as block delete, delete up/down from a specified line, re-numbering.
Only the lines, - no GOTOs or GOSUBs - and various checks on the memory, such as program length.
The next 12 routines are for entering machine code into REM statements, in hex only, and extending and modifying both the machine code and the REM statement. There is also a very useful hex dump facility to view an area of memory which gives eight columns of hex addresses and the data in them.
Sixteen more routines contained in the same EPROM deal with the screen display and, together with a 2K RAM stored at 14K-16K on the same board, allow you to store machine code on TV screens in non-Basic RAM to be recalled later. That makes a total of 38 routines in one 2K EPROM.
EPROM II concerns tape routines, including a RAPID load and SAVE. The other routines allow you to verify and identify a Sinclair SAVEd program.
EPROM IV contains a very good ZX-81 monitor program. It requires also that the board be fitted with 2K of RAM at 14K-16K to store the monitor screen, stack end scratchpad. All the system variables are saved and the various Z-80A registers can be set before entering a machine code routine.
The Spectrum EPROM board also has the facility to be switched out of the memory map by input/output port. It has a blank 2K EPROM fitted - EPROM 1 - and costs £19. EPROMs II to IV cost £10 each and are available only for the ZX-81 at present. Eprom Services is at 3 Wedgewood Drive, Roundhay, Leeds LS8 1EF.