On Thu, 12 Apr 2001, Nicolas Welte wrote: > g.baltissen@hccnet.nl wrote: > > > > Hallo, > > > > While writing the article it occured to me that the combination of IO1 or > > IO2 and $D7xx doesn't sound to bad. This certainly will be atractive to > > people with a C128 and SCPU. > > > > Another one is IO1 or IO2 and $8000..9FFF. The only disadvantage that I see > > for the moment is that a write to this area also overwrites the contents of > > the underlaying RAM. But I thought it is still worth mentioning. > > I think, if you enable Ultimax mode, there is no RAM that can be written to. > This way you can use about every memory location above $1000 to map in your > own I/O. I just wonder if the SCPU is compatible with this mode. After _very_ careful interpretation of the PLA's reverse-engineered sourcecode, Bogax and I have decided that unless you're writing to the I/O page, you can't not write to ram. The only thing that throttles the WE line on the internal dram is the I/O outputs on the PLA - 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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