I'm sure lots of work would need to be done to use z80 to control the SID.  Maybe the z80 SID emulator people can help with this.

The SID was never controlled by the interrupt when I played with it.  And it had analog filters.  Not sure how the SpecNext is going to support that without adding a capacitor/resistor network for the filters.  It'd be rubbish in software.

The Lyndon Sharp is active? I've been trying to get in touch with the man for ages, to no avail.

Lyndon Sharp goes by the name Nodalmighty on the SpecNext forums.

He just quoted one of my posts here: http://www.specnext.com/forum/viewtopic … 0d7b#p1780

How do you think 1-bit engines like zbmod will sound on it?

Will port contention still be there if selecting 48k mode ?

TURBO SOUND NEXT

The internal Spectrum Next and TBBlue Turbo Sound Next interface implements three selectable PSGs, giving access to 9 sound channels plus 3 noise channels. Additionally we have the MOS IC 6581, the Sound Interface Device, aka ‘SID’.

The selection of the current sound IC is done by writing a value in the I/O port 0xFFFD, as below:

Bit 7 = “1”
Bit 6 = Left audio (“1” enabled, “0” disabled)
Bit 5 = Right audio (“1” enabled, “0” disabled)
Bit 4 = “1”
Bit 3 = “1”
Bit 2 = “1”
Bits 1 and 0 as

“’11”: Selects the first PSG (default);
“10”: Selects the second PSG;
“01”: Selects the third PSG.
“00”: Selects the SID.
For example, to select the second PSG, sound on both audio outs:

LD BC,0xFFFD
LD A, 0xFE ; 1111 1110 binary
OUT (C), A

To select SID on right audio only:

LD BC,0xFFFD
LD A, 0xBC ; 1011 1100 binary
OUT (C), A

Commands and data are sent to the standard I/O ports and will be redirected to the currently selected IC.

(to set a register)
LD BC, 0xFFFD
LD A, XX ; select the register: 0 to 15 for PSGs, 0 to 24 for SID
OUT (C), A

(to write to the selected register)
LD BC, 0xBFFD
LD A, XX ; the register value, 0 to 255
OUT (C),A

(to read a selected register)
LD BC, 0xBFFD
IN A,(C)

Ha, ha, I know what you mean on the FM front!

Folks questions and Victor's answers from various points in the thread.

Q:How much LEs takes SID implementation in Next
A:SID implementation 900 LEs. AY, 600 each.

Unfortunately, "big" FMs, only at external bus,
I tested one with more than 50000LEs, but cant remember which FM now.

Q:There is also ePSG8192? http://passionoric.free.fr/eng/project/hsound.htm

A:This is a well known project and have already tested it personally (and probably any other you find). This particularly occupies 35000 LEs, (remember Next had only 9000 and now about 16000 LEs). This ic ALONE already occupies the space of two Nexts. And this VDHL source is still incomplete, missing the ADPCM part.

A:Anyway, I'll be happy to design an open hardware interface with real FM ICs. And Piotr Bugaj can assemble and distribute if he want or anyone can order then PCBs from OSH Park and assemble at home.

A:Unfortunately it's not a catalog where we will simply choose a sound ic and it will be there. The YM2413 was chosen for a number of factors: open code, integration with existing synthesis, space occupied and how much it could add to the sound interface.

A:SID was included for the same reasons the YM2413 was selected. SAA and SN76489 likely to be included also, same reasons

Q:What language is the core written in VHDL?

A:Was written in VHDL, but really doesn´t matter. The synthesis is made "compiling" the sources. Can be VHDL, Verilog, Schematic, whatever... (you can mix all together). And you get a bitstream file on the end, to program the FPGA

A:3 separate AYs = 9 channels, plus SID, another 3 channels, plus FM, another 9 channels. Turbosound Next is compatible with current TS and extend some functionalities to the new ICs

A:Unfortunately, for a better sound than we have today, only with an external interface, as Piotr has already pointed out. ...I know that it is not possible to bring any of these CIs to the project because they simply don't fit into the logical units available on FPGA. It's not me who doesn't want to have the best for the project, it´s just the task can't be achieved.

Did you have this discussion before they upgraded to the SLX16? Maybe at least OPL2 will be possible after all, who knows On the other hand, I'll probably stick to the beeper anyways. I need those limitations, with FM I'd just be stuck tweaking sounds all day.

Yeah, I assume it's the same LS. He's a member the Next Facebook group.
I asked his opinion during the discussions about sound on the Next. There was chat around the YM2413 FM being replaced with the YM2608 or the YM2203 until Victor T pointed out there simply wasn't enough LE's available to bring about any of the big FM chips.
Lyndon said: "I'd be happy with the 2413's big brother, the 3812. same but with 9 independent wave and adsr control rather just the global one."

Like I say, I don't know him but can certainly send him a message and point him in this direction.