I'd recommend contacting CMD directly and ask permission to implement a JiffyDOS COMPATIBLE protocol in your device. Specifically state that you are coding your own KERNAL so they know you're NOT pirating their product. --- ncoplin@orbeng.com wrote: > >The C64's original kernal rom isnt that different > from the vic20's kernal > >rom. It's simply shifted up 3 bytes because the > basic rom needs a jmp$e000 > >to span the gap the I/O space causes between the > two roms. In the vic20, > >these roms are adjacent in the memory map, and the > jmp is unneeded. You > >most likely could, with careful examination, modify > all I/O accesses to the > >CIAs to point to the VIAs in the vic20, and shift > the routines down 3 > bytes, > >then reassemble them. If someone knows if JD uses > features not present in > the 6522, I'd love to know ;) > > I agree that it really wouldnot be all that > difficult to translate between > the two kernals and create a patched VIC20 kernal. > The CIA timers are used > for measuring delays between signals etc, but as > this is all free-running > clock stuff, the 6522's counters should handle it > also... most other stuff > is done as delay loops, and functions such as > switching off sprites etc > could be removed to clean up the code.... > > The main issue I feel is copyright vs patent. CMD > has the copyright to the > JD code, but has the transmission protocol been > patented. If it hasn't then > provided one simply didn't copy the C64 or C128 > code, a VIC20 version of JD > could be created.... Unfortunately I don't know the > answer to the patent > /copyright question.... it would be good to know as > I intend 64HDD to > eventually offer JD protocol support. > > > PLEASE TAKE NOTE: > > The contents of this email (including any > attachments) may be > privileged and confidential. Any unauthorised use of > the contents > is expressly prohibited. If you have received this > email in error, > please advise us immediately (you can contact us by > telephone > on +61 8 9441 2311 by reverse charge) and then > permanently > delete this email together with any attachments. We > appreciate > your co-operation. > > Whilst Orbital endeavours to take reasonable care to > ensure > that this email and any attachments are free from > viruses or other > defects, Orbital does not represent or warrant that > such is explicitly > the case > > (C) 2000: Orbital Engine Company (Australia) PTY LTD > and its > affiliates > > - > This message was sent through the cbm-hackers > mailing list. > To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tml.hut.fi. ===== Get a FREE 6Mb webmail box from go6502! - http://www.geocities.com/profdredd As low as 2.99% Intro APR from NextCard! - http://www.nextcard.com/index6.html?ref=aff0074521 PayPal is the FAST FREE and SECURE way to send money! - https://secure.paypal.x.com/refer/pal=profdredd%40yahoo.com __________________________________________________ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/ - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tml.hut.fi.
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