★ HARDWARE ★ Advanced Eprom Expansion Board|Amstrad Computer User) ★ |
| Memoire - Microgenic - Advanced Eprom Expansion |
Expanding horizons John Kennedy puts a ROM board through its paces. MicroGenic first made the move into the home computer -market when one of the directors saw the state of the products currently available. Appalled by what it saw as a general lack of quality, MicroGenic developed the Eprom Expansion System from scratch. Only the most reliable designs and best available components were to be used, and the result is the MicroGenic range of CPC peripherals. The first element in the system is the Advanced Eprom Expansion Board. ROM boards are difficult things to review; they either work or they do not. This one works. The board is supplied uncased and holds up to eight eproms. It measures about 17 x 3 cm and has a flow-through connector. It comes with a big red button, two slide switches and a bank of eight dual in line switches. The big red button is a reset switch; it is nice to have such cold reset options, but pressing it might just be too easy -even, if you are a very clumsy sort of person, by accident. However, I have not managed to press it by accident, and I am no ballet dancer. It does come in useful when you use the first slide switch, which allows all the eproms to be switched off in one go. Once it is clicked and the reset button pressed, the computer powers up with all systems go and Protext now only a vague memory. This is useful with some programs, especially games, which will not work with any ROMs present. A small LED indicates whether or not the ROMs are on. The other slide switch is used to allow the eproms to operate under ROM numbers 8 to 15. This allows two such boards to be connected at once, just in case you have more than eight eproms. CPC464 owners should bear in mind that only extension ROMs can be used in these positions; 664/6128 owners can use all types of ROM here. This is a consequence of the design of the computers, and nothing to do with the ROM board. The bank of horrid, fiddly DIL switches controls individual eproms and whether they are accessed or not. The board is well built, and does everything you could expect a ROM board to do. As ROM software becomes more popular, people are starting to complain as their systems start to malfunction because of the large quantity of chips lumped on the back. The MicroGenic peripherals use highquality components and a buffering system to ensure that the cumulative effects of various add-ons are minimised. And now we come to the Eprom Programmer - or blower as it is referred to by those in the know. This one will program only the newer 12-volt chips, but as the 21.5-volt ones have more or less been superseded, this is not necessarily a major flaw. Both 8K (2764) and 16K (27128) types are catered for. The Programmer also comes uncased and connects either directly to the computer or can be bolted to the MicroGenic ROM board to form a very stable unit. Clearly, the designers envisaged that whoever bought the blower would either purchase their ROM board at the same time or would already own one. The first stage in programming an eprom, is getting the actual code together. With the MicroGenic system, the code to be burnt into the chip may exist in RAM, or on another ROM. If another ROM is to be copied, it can either be placed in the programming socket and have its contents stored in RAM, or it can be plugged into the ROM expansion board like any other ROM. This makes mass-producing ROMs very quick and easy indeed: bonus marks to MicroGenic for this. The next step in programming involves inserting the chip into the Programmer board. On other systems this can be extremely frustrating and/ or painful; several times the wretched things have flicked round and bitten me by inserting their little legs into my fingers. But blood stains on your keyboard are now a thing of the past because a Zero Insertion Force socket is supplied as standard. How, I ask, could anyone live without one? To avoid any strain on the CPC power system, a small mains transformer is connected to the board before programming can begin. The ROM-based programming software, which is as user-friendly as the rest of the system, checks for this. There are even two little red and green LEDs to indicate whether it is safe to insert the eprom into the Zif. It is so easy to use I would be tempted to let my mother have a go . . . The software is very fast in use, using an 'intelligent' algorithm which programs the eprom as fast as is possible. The more reliable (and slower) standard algorithm is available for those extra stubborn eproms if this fails. With the ROM board and programmer stuck on the back of my CPC I feel I have a complete ROM expansion system. It is fast, reliable and probably the best available. It is the ideal system for those wanting to explore the exciting prospect of DIY eproms for the first time, or for those who wish to expand their present system.
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