the other thing to note after checking the logic for the 74139 last night is that the inputs need to be swapped to that given below if the outputs are going to be on C and D > -----Original Message----- > From: Richard Atkinson [SMTP:rga24@hermes.cam.ac.uk] > Sent: Tuesday, 6 July 1999 19:15 > To: cbm-hackers@dot.tcm.hut.fi > Subject: Re: Looking for YMF262 > > On Mon, 5 Jul 1999, Ruud Baltissen wrote: > > > I once connected a MGP-card to my C64. The card disappeared during > moving from > > one houde to another. > > If the sound blaster only uses I/O, one half of a 74LS39 will do the > trick. > > Connect the PHI2-clock with input A and the R/W-line with input B. > Output C > > reflects the needed WR-line, output D the needed RD-line. Connect the > IRQ-input > > thru an invertor with IRQ5 of the card. The only thing I don't have a > solution > > for is the DMA. > > You must hardwire the addresslines A8 and A9 so that the card sees the > range > > $200-2FF. The AEN-line is connected to PHI2-clock AFTER it has been > inverted. > > Can you point me to an ISA bus reference? I'm afraid I know nothing about > how it works - whether it's multiplexed or not, what the timing of the > address lines, READ# and WRITE# lines is like, how DMA request and > acknowledge lines work, etc etc etc > > > For those interested how I connected the MGP-card which needs > RAM-addressing as > > well: I added a 8255. Two ports I used for A8..A19 and one line I used > for > > telling it was an I/O- or Memory-operation. The other lines I used to > read the > > IRQ-lines of the ISA-slot. These lines were connected to the IRQ-input > of the > > C64 thru a NOR-gate. > > I propose that the SoundBlaster 64 interface use non-Plug'n'Play cards > configured for the 'normal' SoundBlaster settings - ie. 220h - 22Fh, > certain IRQs and DMAs. > > > Richard > > - > This message was sent through the cbm-hackers mailing list. > To unsubscribe: echo unsubscribe | mail > cbm-hackers-request@dot.tcm.hut.fi. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tcm.hut.fi.
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