"Jun Sung Kim (???)" wrote: > > Hi again, > > Maybe some of you misunderstood me... > > I want the minimum configuration NOT for MSX standard > but for EXECUTING EXISTING BIOS.
> ... > > * PPI is needed to set up address space because of the slot/page conception > of MSX standard. > * So PPI must be configured at a very early stage of boot sequence. .... > * Hmmm... To configure PPI, boot codes in ROM should be executed. > * That ROM should be configured in memory space correctly before exection of > the codes. > * To configure that space, PPI should be configured... !#$%^&* ^^ I think you could run the BIOS without PPI/A8 register if you have the ROM fixed on 0000-7FFF and RAM in C000-FFFF: all writes to the A8 port are ignored; all reads from that port will return nonsense, but the BIOS will probably use that nonsense (after masking some bits to select a slot) to write it back to A8, so this won't do any harm. It will appear for the BIOS that you have 4 slots filled with BIOSrom and RAM. Of course you will encounter other difficulties (like reading nonsense from the keyboard...) Regards, Jon _______________________________________________ MSX mailing list ([EMAIL PROTECTED]) Info page: http://lists.stack.nl/mailman/listinfo/msx
