I would like to tell you a little bit about what I would like to do, as your technical editor. First of all, letters. Much of what I would like to do for the magazine involves answering your letters. I don't mind whether they are on "I'm having trouble doing this...", or "How do I do this...", or even requests for articles on how to do certain tasks. Think of me as the Rupert Goodwins of Emulate.
I am including for this month's issue an article on how to convert tapes to work with emulators, from a PC point of view. I am also including a .TAP file containing the latest version of SPECTEST, my Spectrum tester, which is fairly good, and much faster than the earlier versions (if any of you ever used those).
To get in touch with me, for requests, articles, and similar, you can e-mail me: phil@hedgford.demon.co.uk, or you can fax articles. The number is 01543 428082. (If outside UK, dial international prefix then 44, then the number, omitting first 0)
Queries will only be answered in the magazine as a general rule.
A fairly simple solution which will not cost much money is to use Pedro Gimeno's emulator called SPECTRUM. It is possible that you have tried to read the instructions, only to discover that they are in Spanish. Not to worry, the relevant parts are included here:
What you need is a lead with a connector to suit the EAR socket on your tape recorder, usually a 3.5mm mono jack plug, on one end and a 25-pin male D-plug on the other. The tip of the jack plug wires to pin 13, the sleeve to pin 25. This lead connects to the LPT1 port on the PC. You will also need a voltmeter, in order to test the output voltage from the tape recorder, which must not exceed 5 volts, or you may damage your PC. Having done that, you should be able to load the tape in the same way as on the original Spectrum. Having loaded it, snap it to your hard disk.
Advantages: Cheap, fairly reliable, works with most standard loader schemes.
Disadvantages: Not suitable for 128K games, snapping may affect randomness (e.g. Colossus Bridge), not suitable for many loader schemes. Emulator itself unstable. Difficult to work with.
The alternative is to get the registered Z80. In order to handle tapes with this, you will need a tape interface. You can construct this yourself, like I did, using the circuit diagram that comes with Z80, or you can buy one, like I did later on, from Brian Gaff. This has the advantage of not having wires to break, and it is also two-way.
Whichever interface you have, you can connect it to any parallel printer port. You need to calibrate it for 50% deflection in the DIAGRAM program or 128 tape tester.
The tape interface can be treated just like the EAR and MIC ports of a Spectrum. The difference is that the speaker does not echo the tape sound.
Z80 has loader routines that will handle most standard loaders regardless of the speed of your machine. For non-standard loaders, you must do all of the following:
Set R-register emulation and LDIR emulation ON.
Set emulation speed to 100%: failing that, get a tape recorder that runs at the highest relative speed you can obtain.
After the standard blocks, switch to REAL mode until the program is loaded.
You can snap a program to the hard disk. For games in which randomness is affected, or those which load levels, provided they use a standard loader, you can use a mirror .TAP file. This behaves rather like a tape.
You can, of course, try connecting the tape recorder to your sound card. This is not usually as reliable as the printer port connection. However, you can sample a tape to a .VOC file, and use Z80's .VOC file support, load a non- standard loading program or levels. This even works on slow machines. The only problem is that some samplers cause interference, which will cause the loading to break. This may be worth doing with a good quality setup.
Loading: Set up .TAP file, or insert tape.
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