RE: BASIC and System ROM replacements

From: Baltissen, GJPAA (Ruud) <>
Date: Mon, 27 May 2013 05:57:14 +0000
Message-ID: <>
Hallo JG, 

> Something I'd find useful is being able to have more than 16K
> available in the 16K cartridge slot, and to be able to page
> the cartridge out. Then I could copy greater than 16K code
> from the cartridge to RAM, than page out the cartridge.

A 27512 EPROM can handle 64 KB. A 74LS273, a resetable latch, can handle the pages plus 'paging out' the cartridge. 
After a reset the C64 'sees' the cartridge and starts executing its program. The first thing the program does is copying the actual copy part into RAM and executing it. At the end of the bank the program sets the 273 to another value and start copying the next bank. This is repeated until the whole program is copied. The last thing left to do is setting a bit of the 273 that disables the cartridge.

    / __|__
   / /  |_/     Groetjes, Ruud
   \ \__|_\
    \___|       URL:

De informatie in dit e-mailbericht is vertrouwelijk en uitsluitend bestemd voor de 
geadresseerde. Wanneer u dit bericht per abuis ontvangt, verzoeken wij u contact op te 
nemen met de afzender per kerende e-mail. Verder verzoeken wij u in dat geval dit 
e-mailbericht te vernietigen en de inhoud ervan aan niemand openbaar te maken. 
Wij aanvaarden geen aansprakelijkheid voor onjuiste, onvolledige dan wel ontijdige 
overbrenging van de inhoud van een verzonden e-mailbericht, noch voor daarbij 
overgebrachte virussen.

APG Algemene Pensioen Groep NV is gevestigd te Heerlen en is ingeschreven in het 
handelsregister van de Kamer van Koophandel Limburg onder nummer 14099617

The information contained in this e-mail is confidential and may be privileged. 
It may be read, copied and used only by the intended recipient. 
If you have received it in error, please contact the sender immediately by 
return e-mail; please delete in this case the e-mail and do not disclose its 
contents to any person. We don't accept liability for any errors, omissions, 
delays of receipt or viruses in the contents of this message which arise as a 
result of e-mail transmission.

APG Algemene Pensioen Groep NV is registered in the trade register of the Chamber 
of Commerce Limburg, The Netherlands, registration number: 14099617

       Message was sent through the cbm-hackers mailing list
Received on 2013-05-27 06:01:31

Archive generated by hypermail 2.2.0.