A version of the Microdrive Emulator ROM cartridge is available explicitly for use with the SPECTRA interface. It utilises the shadow ROM facility provided by the SPECTRA interface and therefore does not need to include a patched version of the Spectrum ROM. This frees up additional space for the virtual microdrive cartridge, increasing its capacity from 75K to 90K (which is 5K more than the minimum advertised for a real microdrive cartridge).
The SPECTRA version of the Microdrive Emulator has a number of advantages over the standard Interface 2 version:
- It supports a higher capacity virtual microdrive cartridge since it is not necessary to include a modified version of the Spectrum ROM (90K as opposed to 75K).
- It is more compatible with existing programs since the Spectrum ROM does not need to be patched to accommodate the ZXC3 paging mechanism (the character set bitmaps do not require relocating).
- Since the real Spectrum ROM is used, the emulator will operate correctly with alternate language versions of the Spectrum.
- The Z80 I register does not need to be be set to a specific value.
Note that configuration switch 3 of the SPECTRA interface must be set to the 'ON' position to enable the shadow ROM facility in order to use this version of the Microdrive Emulator.
Two versions of the Microdrive Emulator for use with the SPECTRA interface are available and these emulate the edition 1 and edition 2 ROMs of the ZX Interface 1. Both can be downloaded from the Microdrive Emulator ROM cartridge page.