Hallo Nicolas, I've some experience with a CP/M-module for the C64 and I only can acknowledge what Marko writes. If I wanted to change the memory configuration, I had to activate the 6510 again. Just FYI, I think I know the reason why the CP/M-module for the C64 became a flop. The NMI- and IRQ-line of the C64 were NOT connected with the Z80 inside the module. I wonder what kind of tricks a programmer had to use to read the keyboard, RS232 or whatever interrupt-dependent device. Groetjes, Ruud Aan 17-11-99 13:09, in bericht <Pine.OSF.email@example.com>, =?ISO-8859-1?Q?Marko_M=E4kel=E4?= <firstname.lastname@example.org> schreef: > On Wed, 17 Nov 1999, COPLIN, Nicholas. wrote: > > > the questions I have are: > > 1) what memory map does the DMA see? is it the one defined by the 6510 port > > or are the port lines also Z-stated? > > >From my somewhat limited experience with the REU, it is the one defined by > the 6510. > > > 2) if the mem-map is still the 6510 view, then do write throughs to under > > the ROM still write to RAM > > I think so, yes. The DMA device simply replaces the processor. > > > 3) how does one DMA to write to the 6510 ports 0x0000 and 0x0001??? > > One doesn't. It's also difficult to write to the memory locations 0 and 1 > with the 6510, but it's possible and I've done it. > > > 4) can the IRQ /NMI lines be "read" from the expansion port or are they > > buffered only for generating requests? they look unbuffered to me..... > > Yes, they are bidirectional in that sense. > > > The contents of this email (including any attachments) may be > > privileged and confidential. > > Does this mean that your company is going to develop an accelerator > cartridge for the C64? :-) > > Marko > > - > This message was sent through the cbm-hackers mailing list. > To unsubscribe: echo unsubscribe | mail email@example.com. > - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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