The ZX Spectrum Reverse Engineering and Clone Desgin Blog


A site dedicated to the reverse engineering of the ZX Spectrum and related projects.

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The Loading Test

Jun 26, 2007

Having built the cassette interface I hooked the headphone socket of my Linux laptop to the Harlequin EAR socket, and using playtzx I 'simulated' being a cassette player. I downloaded a few Spectrum games from the World Of Spectrum, typed the obligatory LOAD "" on the Harlequins keyboard, and watched!!!!

Here are some screenshots for your viewing pleasure!

Firebirds Vectron

MicroGens Stainless Steel

Hewson Consultants, Quazatron

Quicksilvers Aquaplane, and Design-Designs Dark Star

As you can see, things are not quite as they should be with Dark Star and Aquaplane, two games deliberately chosen as they require exact interrupt timing. Dark Stars top border logo is too far over to the left hand side of the screen, and Aquaplanes full screen horizon is too high in the border. Interestingly, Vectrons 'full screen' post-loading, pre-game screen (above) displays correctly.

There is something clearly not quite right with the interrupts, so the excitement over, it's time to load up Ramsofts floating bus and interrupt test program, and to put the Harlequin through it's paces....