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Last missing to make whole of it to make sense to me are _IORD/_IOWR signals. How would I replicate this?terriblefire wrote: 07 Oct 2020 20:32 The solution to this is to assign one of the INTSIG wires to A5 in the CPLD.
assign INTSIG[x] = A[5]; etc.
This is why i have spare lines for. :)
IORD = Bus request + RW higharkadiusz.makarenko wrote: 07 Oct 2020 21:06 Last missing to make whole of it to make sense to me are _IORD/_IOWR signals. How would I replicate this?
terriblefire wrote: 07 Oct 2020 21:25IORD = Bus request + RW higharkadiusz.makarenko wrote: 07 Oct 2020 21:06 Last missing to make whole of it to make sense to me are _IORD/_IOWR signals. How would I replicate this?
IORW = Bus Request + RW low
So you dont need to emulate these... this can be abstracted away.
Yeah i think thats the case. I cant remember if there was also a BUSREQ pin?arkadiusz.makarenko wrote: 07 Oct 2020 22:22terriblefire wrote: 07 Oct 2020 21:25
IORD = Bus request + RW high
IORW = Bus Request + RW low
So you dont need to emulate these... this can be abstracted away.
Can I just read only value of /RW then? I will be decoded address + RW + bits of Address line, so I would have all states required to emulate RTC?
Those are available on edge connection, but a lot of ?? on descriptions.terriblefire wrote: 07 Oct 2020 22:26Yeah i think thats the case. I cant remember if there was also a BUSREQ pin?arkadiusz.makarenko wrote: 07 Oct 2020 22:22
Can I just read only value of /RW then? I will be decoded address + RW + bits of Address line, so I would have all states required to emulate RTC?
As soon as I will have something to show...terriblefire wrote: 08 Oct 2020 19:46 Im happy to test this out on my CD32 when you're ready. I still have this riser and a CD32 here.
Code: Select all
module address_decoder(
input [23:16] A,
input A3,
input A5,
output INTSIG2,
output INTSIG3,
output INTSIG5
);
assign INTSIG3 = A3;
assign INTSIG5 = A5;
assign INTSIG2 = A[23:16]==8'b1101_1100; //RTC registers at $DC0000 - $DCFFFF
endmodule
Code: Select all
NET "A3" LOC = "P32" ;
NET "A5" LOC = "P34" ;
NET "A<16>" LOC = "P47" ;
NET "A<17>" LOC = "P48" ;
NET "A<18>" LOC = "P57" ;
NET "A<19>" LOC = "P56" ;
NET "A<20>" LOC = "P51" ;
NET "A<21>" LOC = "P52" ;
NET "A<22>" LOC = "P50" ;
NET "A<23>" LOC = "P49" ;
NET "INTSIG2" LOC = "P23" ;
NET "INTSIG3" LOC = "P24" ;
NET "INTSIG5" LOC = "P12" ;