As far as I recall, in fact you can run the "classic" Basic52 v1.1 on any speed - while the XTAL pseudovariable cannot be set much higher than 12MHz, it can be worked around as far as timing is concerned - simply set it to a fraction of the real crystal frequency and multiply the timing elements in your program accordingly to compensate. There will be a problem - the EPROM programming timing won't be ok, but are you really going to use an eprom to store the BASIC program?

You can of course use my modification (there is a link somewhere at my 8052com webpage) but it is dedicated to AT89C52ED2 (it's unlikely one cantoday get the Temic's RD2 which I used originally). You can use it for a generic '52, and it fixes the XTAL problem, but ... it expects the "EPROM" with the permanently stored BASIC program to be in code space rather than data space; it is bigger than the original 8k (~10k or so); the extensions won't work wthout modification; the EPROM programming won'twork, of course; on startup it tries to enable the extra RAM in ED2 so it writes into some SFR which may have another meaning in other derivatives...

But of course I will be happy if you try it - and let us know on the results.

Have fun!


Jan Waclawek