CPC-SID

[Bryce]

But that's not a CPC playing an MP3, it's an MP3 player that uses the CPC as a set of buttons! An insult to the CPC! Being degraded to something that could be done with a few cheap switches. If the Z80 doesn't process the data, then why bother connecting the CPC at all?

Bryce.

[TotO]

But that's not a CPC playing an MP3, it's an MP3 player that uses the CPC as a set of buttons! An insult to the CPC!

So, please, considerate all devices are an insult for the CPC, because you OUT data with the CPU on ports...

Being degraded to something that could be done with a few cheap switches.

Hope you're jocking...

If the Z80 doesn't process the data, then why bother connecting the CPC at all?

Because a computer don't need the CPU for processing an audio stream since 25 years ago...


OK... Decoding MP3 with Z80... And After ? OK it's finish and crappy, and then ?
It's just a geek challenge with some rasters ?


Sorry, but I don't need that on my CPC today!

[Ygdrazil]

I partly agree with you!

But the CPC would still be responsible for the sequence of playback events :-) So the Z80 is not completely idle! 

/Ygdrazil

But that's not a CPC playing an MP3, it's an MP3 player that uses the CPC as a set of buttons! An insult to the CPC! Being degraded to something that could be done with a few cheap switches. If the Z80 doesn't process the data, then why bother connecting the CPC at all?

Bryce.

[TotO]

But the CPC would still be responsible for the sequence of playback events :-) So the Z80 is not completely idle!   

And you can use it for doing stuff while the music still playing (loadings too)

[Bryce]

Actually I wasn't joking. For me an expansion is a "Peripheral" for the CPC, ie: the CPC / Z80 does the main task and uses some extra hardware to make it possible. But in your example above, the the MP3 player will work perfectly without a CPC being attached.

Of course all CPC devices aren't an insult. If I add an S-Video output, RAM module, ROMBoard, modem, USB socket, LAN card or HxC to the CPC, then they are all there to enhance what the CPCs Z80 is able to do. But connecting an MP3 module that just uses the CPC as a set of buttons is ridiculous. It would be like interfacing the CPC to a Blu-ray players play/stop button and and claiming the CPC could play 3D films. If the Z80 isn't doing the main task, then the CPC isn't really required. It's just a bulky remote control.

Of course that's just my opinion, go ahead and install a CPC inside an Airbus and claim it can fly. 

Bryce.

Edit: I don't know the YM2203 Is it widely available? What was it used in? And what can it do better than the SID? I know many people don't like the SID because of it's C64 history, but it's still a great sound chip, that the Z80 could do great things with.

[TotO]

Because it's easy to do, cheaper, and because you can use the CPU for doing other task while playing, it's not suitable for you ?
I don't want to stay closed in "80s"... CPC can do modern stuf today and we have to use thoses opportunities. (SD as Floppy, ...)


After all, please, if you really want to drive a new audio chip with the CPU, please use an YM2203 instead of...
SID sound like an insult for the CPC...

[TotO]

Edit: I don't know the YM2203 Is it widely available? What was it used in? And what can it do better than the SID? I know many people don't like the SID because of it's C64 history, but it's still a great sound chip, that the Z80 could do great things with.

OK, I have moved my edit after, but you see it.   

YM2203 was an advanced version of the CPC AY with FM too.
So by combining both, you got 6 AY channels and 3 FM channels (great for bass and drums).

[Bryce]

SD as Floppy (HxC) is modern but still very much ok in my book, because it is there to enhance the data storage of the CPC. The CPC is still the master.

Hmmm, the YM2203 does look interesting, but I don't have one (yet). I have a YM2149 here, which is the YM2203s poor country cousin and doesn't offer anything more than an AY. So not worth the bother. If I can get a YM2203 I will definitely look at interfacing it.

Is the YM2203 still available anywhere?

Why is the SID an insult for the CPC?

Bryce.

[TotO]

I found that... Please, listen MP3 at the end of the page :
http://velesoft.speccy.cz/turbosound-cz.htm

Hmmm, the YM2203 does look interesting.
If I can get a YM2203 I will definitely look at interfacing it. Is the YM2203 still available anywhere?

I can order for in China by a friend...

Why is the SID an insult for the CPC?

It's a joke, because it's the C64 identity and not the CPC identity.  


EDIT:
Some musics (from the link) are using FM for melody instead of AY... So that don't sound more like a CPC.
Realy better to use it for some sound effects, drum and bass and keeping AY at main music.


EDIT2:
Many arcade games (Gun Smoke, Ghosts'N Goblins, Robocop ...) use YM2203 for sounds !!!
No smallest version without the DUAL GPIO... :/ But that can be used for other stuffs...

[Bryce]

Ok, now they ARE nice sound interfaces, where the speccy is still doing all the work

The MP3s sound nice, but it doesn't say which card was used for which sample? (My Czech isn't very good).

Bryce.

[MacDeath]

there is already MP3 on CPC... is it the tuner or the peritel box ?


Anyway can't hose soundchip be reproduced by an Arduino mega ?

I saw a SID emulated by such device... so other soundchip may be too...
Just get the wiring schematic and a proper library then.


Also I like the idea to simply add another AY to "only" get the CPC/Plus in 6 sound channels (with some DMA on PLUS) which is quite enough to get sweet and cool stuff.

The schematic for such additional AY already exist yet can probably be improved.


On the other hand, to get the CPC as just a terminal for some stuff is not that useless.
MIDI is more like that, it is not the computer who produce the sound but the various device you connect through the Midi port.


Also some internet on CPC would need the CPC to be more some sort of terminal and graphic card than anything else.

[TotO]

The MP3s sound nice, but it doesn't say which card was used for which sample?

You can read "Turbo AY" (2xAY) and "Turbo AY-FM" (2xAY + FM)

[MaV]

A z80 could never decode and play an MP3 at any reasonable bitrate could it?

No, not possible.

Look at that Z180 System with mp3 decoder hardware:
http://www.ngsystems.z80.de/
Click Z80/Z180 at the left side, then scroll down and choose "MP3-Player" to have a look at how he's done it.

The German wikipedia entry on mp3 decompression details somewhat how it is done:
"Bei der Dekompression werden die Schritte der Kompression in umgekehrter Reihenfolge ausgeführt. Nach der Huffman-Dekodierung werden die Daten mittels inverser Quantisierung für die inverse modifizierte Cosinustransformation (IMCT) aufbereitet. Diese leitet ihre Daten weiter zu einer inversen Filterbank, die nun die ursprünglichen Samples berechnet (verlustbehaftet durch die Quantisierung im Kodierprozess)."

So the steps are Huffman-decoding, inverse quantisation, inverse modified cosinus-transformation. Hm, need I mention that the Z80 is bad at floating point calculations?

Anyway, my 486dx2 (80MHz) from 15 years ago had problems playing mp3s, and that one had a co-processor. Todays mp3-players use special hardware to decode mp3s, and those usually have a 50+MHz ARM chip, which is known to be cycle efficient but lack floating point instructions.

There's no way a Z80 chip can do anything like that without decoder hardware.

[Bryce]

You can read "Turbo AY" (2xAY) and "Turbo AY-FM" (2xAY + FM)

Ah, ok, I was looking at the two MP3 files just above that (Hung-up / Breath of Air) and they don't mention what they were made with Nice base and drums The "electric guitar" in "Difference" is also quite good.

@MaV: That's exactly what I mean. Hardware for the CPC should be focused on making the most of what the Z80 can do, and a Z80 definitely couldn't play an MP3, so let's move on and concentrate on what it can do.

But a new question: What is the best soundchip that's (A) Really easy to find/buy and (B) could be controlled by Z80? I only chose the SID because I know it and it offers some stuff that the AY doesn't have. If there is some super soundchip out there, that could be fed by the CPC, then I would rather do an interface for that... Why take a half step, when a leap is possible

Bryce.

[tastefulmrship]

If there is some super soundchip out there, that could be fed by the CPC, then I would rather do an interface for that... Why take a half step, when a leap is possible

I always loved PAULA! You can't get better than one of those, until you hit PC boards; eg SOUNDBLASTER... and then you're talking silly! You may as well have that MP3 board plugged in!

[TotO]

This evening I'll check for the music I prefert. (don't remember the title)

A great soundchip that you can handle with Z80 is the YM2151 !
Cost around 5$ with its stereo DAC.

EDIT
Datasheet :
http://www.ionpool.net/arcade/gottlieb/technical/datasheets/YM2151_datasheet.pdf

EDIT2
A nice website about soundchips wiring (schematics) :
http://sue.niko.to/ps98/

[Bryce]

I was having a browse through my Datasheets here and I've found one interesting IC, that would be a major leap and probably easy to find: The YM3812 was the IC used on the first generation soundblasters / Adlib soundcards, so you'll probably find them at any garage sale. It's easily interfaced to an 8-Bit system and offers quite a bit more than our humble AY: http://en.wikipedia.org/wiki/Yamaha_YM3812

Bryce.

[redbox]

I still think a CPC-SID is a good idea.  Nick the best bit of a C64 and put it into a better computer = Result.  And I think it's a good idea to adhere to Bryce's sentiment - the CPC is still doing the 'work'. 

However, I was thinking the other day about the Gravis Ultrasound.  This had a nice bit of memory where you could load the samples into for playback.  Just something I thought I'd add to this melting pot 

[TotO]

I was having a browse through my Datasheets here and I've found one interesting IC, that would be a major leap and probably easy to find: The YM3812 was the IC used on the first generation soundblasters / Adlib soundcards, so you'll probably find them at any garage sale. It's easily interfaced to an 8-Bit system and offers quite a bit more than our humble AY

- YM2151 is a 8 channels 4op FM chip + MIDI ports (dreamed by Atari for the ST... But it's another story)
- YM3812 is a 9 channels 2op FM chip

So, YM3812 sound as bad a PC sound at this time.  
YM2151 sound much better. (like R-Type or Ghouls'N Ghosts in arcade)

Here, a nice page about YM chips :
http://www.vorc.org/text/column/hally/ymxxxx.html

[TotO]

However, I was thinking the other day about the Gravis Ultrasound.  This had a nice bit of memory where you could load the samples into for playback.  Just something I thought I'd add to this melting pot 

It's like Paula in far better... But, it's too heavy to handle by a CPC without DMA...

[Bryce]

I think the biggest problem with ANY of these ICs is the availability. It will have to be something that's easy to source, either as a single component or inside something that's easy to get. The SID is a bit strange in that way. The single ICs are offered for €20+ on ebay, but you can get a C64 with one inside for under €10 ?

Regarding the YM2151 - There's an expansion project for the Atari 7800 being built in batches that has a YM2151 inside, but I've no idea where the guy is getting them from

Bryce.

[TotO]

I think the biggest problem with ANY of these ICs is the availability.

No problem in China. All are avaiable in quantity.
I can order for, if it's really used for a project. I already got YM2151, YM2612, YM2203, ...

[Bryce]

I have a source in China too, but the prices aren't what I'd expect to pay. How much did you pay for them. (Send me a PM if you don't want to discuss it here).

Bryce.

[TotO]

Regarding the YM2151 - There's an expansion project for the Atari 7800 being built in batches that has a YM2151 inside, but I've no idea where the guy is getting them from

New from China... Or refurbished from old arcade PCB.

[steve]

@Bryce, how do you feel about adding a Z80 DMA controller to take some of the load off the Z80?