letzter Beitrag von Arsid Builder am
I did this long ago adding stereo to address $D700 with a 2nd SID chip. I think I used a 74LS129 chip. Do I need that with the FPGASID? Because it looks like can pick were to map it in a program?
If not how would I map this to $D700 in a C=64c what I want to use the FPGASID in that I just order today. I all ready made video cables to use pin 7 for the 2nd SID chip. I did this years ago.
-Raymond Day
I'm just curious, why do you need it to be at $D700?
I do not know one 2SID tune that uses $D700 as address for the second SID, do I miss something?
You would have to insert an AND gate (1/4 of 74LS08):
newA5 = A5 & A6
then connect newA5 to the "A5" connection of the FPGASID.
In this case it would react to D700 when it is configured to "D500" because it would only select the second SID when both, A5 and A6 are high.
And yes, I am curious too, why precisely D700 is important. Up to my knowledge there is no software using that Address for a second SID. Please teach us wrong 
My first msg on this board. 
I think I used a 74LS129 chip.
Maybe it was a 74LS139-chip, which has dual 4-output decoders. Just the same chip they used in the Cbm64 when decoding the Vid/Sid/Color/IO-signals, and the Cia1/Cia2/IO1/IO2-signals.
newA5 = A5 & A6
Don't you mean to connect A8 & A9 (with an AND)?
When connecting A5 & A6 (with an AND), than it would respons on a base=address $D400 + %0110 0000, which will be $D460.
Base-Hex => Binair
---------------------------------------------
$D400 => %1101 0100 0000 0000 <=== Default Base-address
$D500 => %1101 0101 0000 0000
$D600 => %1101 0110 0000 0000
$D700 => %1101 0111 0000 0000 <=== Needed Base-address
Edit: Added Attachment forum64.de/wcf/index.php?attachment/168329/
Don't you mean to connect A8 & A9 (with an AND)?
Yes, sorry. My mistake.
Making a new chip select signal with a 74LS139 can be problematic because in that case it should be avoided that the D400 chip select is not active when the D700 select is active as well...
Long ago I put lots of 2nd SID's in people Commodores. I mostly did it for free and I used a chip to address them to $D700 and got stereo players to work there. Could there be a Flash update were can pick $D700. I have all way put the 2nd SID sound on PIN 7 of the U dim plug for audio/video. It was the only one not used. I made the auto video cables for them too.
I did that because I know at $DF00 and $DE00 it can mess up some cartridges and I never had it mess up any thing that I found when addressed to $D700.
-Raymond Day
... why a new thread for the same subject as here: How to map it to $D700 ?
... why a new thread for the same subject as here: How to map it to $D700 ?
must have been an accident - maybe @Raymond Day did not find the old topic so he started a new one. I just merged both topics for now.
But back on topic:
I though about it more in deep. I concluded there is not much to do about mapping the FPGASID to D700.
What actually happens when you enable the D500 mapping in FPGASID is the following:
D400-D4FF: SID1
D500-D5FF: SID2
D600-D6FF: SID1
D700-D7FF: SID2
I think this is exactly what you need.
So if I set the 2nd SID to $D500 it would be at $D700 all so?
-Raymond Day
So if I set the 2nd SID to $D500 it would be at $D700 all so?
Yes!
I got down my old original or 1ST C-64 that I got and later put stereo SID in very long ago and mapped it in to $D700. I looked how I did it and I used a 74LS139 chip.
Put a little sheet mettle between them for like a heat sink.
I had the corners on another chip by it for ground and 5 volts. Pin 1 I cut of the $D400 line and put it on pin 4 of the 74LS139 to the chip select pin, or pin 8 of the 1st SID chip.
Pins 1, 2, 3, and 4 of the 74LS139 put to: A7 pin 1, A8 pin 2, A9 pin 3, and Pin 4 to the old SID chip pin 8 chip select.
Then pin 7 is the CS or Chip Select of the new 2nd SID pin 8.
So on the new 74LS139 that pins would map in like this that makes it easy to know how.
1 = A7 or the old SC of the 1ST SID.
2 = A8
3 = A9
4 = $D400 the new line for the old 1ST SID.
5 = $D500
6 = $D600
7 = $D700
All the other pins are not used they are to nothing, Bent out.
So I guess if I put the pin that you put on the user port to pin 7 it be at $D700. But I guess it mirrors it to $D700 any way when you pick $D500. Going to test this out.
-Raymond Day
The problem with using the DE00 signal for D700 is, that whenever the chip select for D700 becomes active, the D400 chip select from the C64 will also be active. So you'd have to connect the D400 from the LS139 as well.
But why? I already told you that the second SID will be on also D700 when you activate D500. No need to interfere with the existing address decoding logic.
I got down my old original or 1ST C-64 that I got and later put stereo SID in very long ago and mapped it in to $D700. I looked how I did it and I used a 74LS139 chip.
Just curious ... What is your experience level with digital electronics?
Just building existing schematics?
Or do you have some skills in developing electronics by yourself?
Alles anzeigenBase-Hex => Binair
---------------------------------------------
$D400 => %1101 0100 0000 0000 <=== Default Base-address
$D500 => %1101 0101 0000 0000
$D600 => %1101 0110 0000 0000
$D700 => %1101 0111 0000 0000 <=== Needed Base-address
............... 1111 11
Address-bit . 5432 1098 7654 3210
$D400 => %1101 0100 0000 0000 <=== Default Base-address
$D500 => %1101 0101 0000 0000
$D600 => %1101 0110 0000 0000
$D700 => %1101 0111 0000 0000 <=== Needed Base-address
A15..A10 .... xxxx xx .......................... Wired by the Cbm64
A8-wire ................... ^ ....................... Separate wire to the FpgaSid
The address-area $D400-$D7FF is decoded by the address bits A15..A10 by the Cbm64 it self. This whole area (of 1kByte) is originally meant for the Sid.
But why? I already told you that the second SID will be on also D700 when you activate D500. No need to interfere with the existing address decoding logic.
When Andy6510 wrote: When wiring the $D500-wire to Address A8, this is what will happens.
When the A8-line is LOW, Sid1 is activated.
When the A8-line is HIGH, Sid2 is activated.
All other address-lines are ignored, because there is no wire connected to them.
That are the address-lines A9, A7, A6. What voltage they may have (LOW or HIGH), it does not matter.
Because there are no wires conneccted to them, no decoding will occure with these address-lines.
(I intentionally don't mention A5, because that is (more or less) an exeption with the FpgaSid, and that is beyond this explanation.)
So it must easily be seen in my binairy-table, that in the range of $D400 .. $D7FF, there are only two area's when the A8 is HIGH.
And those are the mentioned $D500 and $D700 area's.
