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magoseitor


Newbie


Joined: 17 Feb 2008
Posts: 8

Posted: 08 Mar 2008 08:00:05 pm    Post subject:

hi guys.. i had this idea,

if possible, could it be factible instead of trying to ouput nice music trough the I/O port using pwm, use an external digital to analog converter?

i am just frustrated in playing MOD, (or S3M, IT, whatever tracker format) format music on the ti.

i tried out pplayer and midi68k, and some external tunes, but none of them had even 100% near to MIDI quality...

is it possible to encode MOD format to whatever format the TI calc understands, and then decoding it to digital audio and output it through the I/O port and then to the external DAC?

cheers.

please don't abuse of me, i am a noob, but i have this idea, i just want to know.
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DigiTan
Unregistered HyperCam 2


Super Elite (Last Title)


Joined: 10 Nov 2003
Posts: 4468

Posted: 08 Mar 2008 10:08:57 pm    Post subject:

Yep. It's possible to come up with a new sound program and use an R-2R Digital/Analog converter. With the two link wires, that would give you 4 possible output levels. Then a capacitor on the output would provide filtering of high-pitched noise. This has been done for video, but not sound that I know of.

Also Jim e came out with the RealSound program that plays MP3-quality audio. Again, you can filter out the upper harmonics for even crisper sound. Jim e uses PWM.

In the Sonic thread we were once considering recording real instrument samples to get a MIDI-like system. It was based on the idea that:
Frequency = Original Frequency ( Sample Rate / Playback Rate )

We abandoned the idea after a while.


Last edited by Guest on 08 Mar 2008 10:09:41 pm; edited 1 time in total
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magoseitor


Newbie


Joined: 17 Feb 2008
Posts: 8

Posted: 09 Mar 2008 01:21:12 am    Post subject:

Thanks for the answer DigiTan...

I tried to check out RealSound, but i have a 89Ti, also i wanted to see the code, and see it didn't came with the zipped file :-(

I have another question, is it possible an usb driver for the ti-89 like the 84 has?
Because if we have a nice quality sound with small files (MOD, 100%-alike MIDI), then is good for us; the realsound is a nice idea and app, but you can fit less than 2 min of sound. So, if we could have external storage this would be no problem.

Another question: is it possible to read/write from the multiple ports in the 89Ti at the same time (I/O and mini-USB)

Now about the R-2R DAC, i would like to play with that.
Look, i am a student of electrical engineering, and in 3/5 of the carreer, this semester i am cursing digital electronic and microcontrollers. So, besides what i may learn and apply it to this stuff; i am willing to crunch whatever texts/information/knowledge is necessary to somehow make my ti-89 a factible music player.

Could you please, or somebody, give me the light so i can walk the path?

Thanks.
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TheStorm


Calc Guru


Joined: 17 Apr 2007
Posts: 1233

Posted: 09 Mar 2008 09:57:10 am    Post subject:

Well for the usb stuff no-one has yet to figure out how the usb hardware one the 89t's work hence the lack of msd driver. if you want to look into it go ahead. as for the read and write to two ports at the same time, I'm pretty sure you can but I do not own a 89t so don't take my word for it.
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Liazon
title goes here


Bandwidth Hog


Joined: 01 Nov 2005
Posts: 2007

Posted: 09 Mar 2008 05:40:01 pm    Post subject:

I suspect no one has bothered to write an MSD driver. iirc, I remember that TIGCC was updated some time ago by Kevin Kofler to support the USB on a high level. As to why it's not used much idk, maybe programmers feel not many people have 89tis or something. Kevin mentioned that the USB is not really that much better than the link port, it's just different, but I'm not sure about that. Also, I think since the 89s have a lot of flash space, and perhaps out of lack of interest, there aren't that many sound programs/USB programs for it.
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DigiTan
Unregistered HyperCam 2


Super Elite (Last Title)


Joined: 10 Nov 2003
Posts: 4468

Posted: 09 Mar 2008 09:35:15 pm    Post subject:

magoseitor wrote:
Now about the R-2R DAC, i would like to play with that.[post="121206"]<{POST_SNAPBACK}>[/post]

Yep. Basically the R-2R part is two resistor that take the 2 wires from the link port and do a voltage division. The possible outputs are roughly 6V, 4V, 2V, or 0V depending on which wire(s) are on or off. One resistor has to be equal to the input resistance of your amp. The second resistor needs to be double that.

I heard a while back that TI links have miniature fuses. I'm not 100% sure if the linkport can directly power a speaker without blowing them. Headphones are okay, but with speakers, you may have to isolate it from the calc with an amplifier. I'm not sure what the current limit for TI links is.

Since the sound quality doesn't have to be great, it can be a really simple amplifier. If you're taking Electronic Circuits you could probably rig up one of their Inverting or Non-Inverting op-amp circuits to do it. Or 1 transistor.

Overall, it just kind of depends on how big the speaker is. The larger the size, the bigger the system gets.


Last edited by Guest on 09 Mar 2008 09:38:09 pm; edited 1 time in total
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magoseitor


Newbie


Joined: 17 Feb 2008
Posts: 8

Posted: 10 Mar 2008 03:58:23 am    Post subject:

Many thanks for the answer guys!! :biggrin: i guess i'll be playing and playing until i figure out how the f**k i can play mod with quality or make usb storage while taking my courses... (so so far...) but at least i'll have fun Smile

cheers, and again, seriously thank you.
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DigiTan
Unregistered HyperCam 2


Super Elite (Last Title)


Joined: 10 Nov 2003
Posts: 4468

Posted: 10 Mar 2008 04:06:07 am    Post subject:

Yep. TI-89 has a serious amount of memory, so it kind of makes sense that there should be more sound progs for it. A midi system would be really useful for games too.
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CoBB


Active Member


Joined: 30 Jun 2003
Posts: 720

Posted: 10 Mar 2008 08:44:54 am    Post subject:

I don’t think playing existing module music on the Z80-based calculators is feasible, there’s simply not enough raw power to perform the mixing at any sensible quality (just consider for starters that you need at least one multiplication per channel per sample to handle volume). If all the samples fit in 16k (which basically leaves us with chip music) and we leave the amplitudes alone, then a few channels might be possible. However, that would leave little time for everything else, so using such a player in the background is out of the question.
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Jacoby


Newbie


Joined: 10 Mar 2008
Posts: 9

Posted: 10 Mar 2008 09:47:00 am    Post subject:

CoBB wrote:
there’s simply not enough raw power to perform the mixing at any sensible quality


True, but you can always outsource some of the processing work. For example:

MP3 decoder IC

There's no point in reinventing the wheel - there will be hardware packages out there to do most of the stuff you want to do without taxing the TI too much. Ultimately, though, you just end up using the calc as a storage medium, and not the music player itself. Still, if you're going to have a DAC on the outside anyway.. why not?
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magoseitor


Newbie


Joined: 17 Feb 2008
Posts: 8

Posted: 10 Mar 2008 03:09:58 pm    Post subject:

I came up with more stuff in class today, i am just writting what i thought, i haven't yet read any information about it, so i'm open to flames Razz hehehe

Ok, the MOD file is supposed to be samples+structure... we take the samples, and the structure, rearrange it to whatever the 89Ti likes, making a new ti-readable file. We make a new player that do the same as the mod players: throw out the samples according to the structure, plus, some effects. That supposed sampled music goes out in series through the I/O port. We put in the middle a series to parallel converter and finally that R-2R DAC (or other better [or comercial]).

Using 8 or 16 bit.

so the newbie has made its humbble aport :-P

cheers
and thanks for the posts...
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CoBB


Active Member


Joined: 30 Jun 2003
Posts: 720

Posted: 11 Mar 2008 12:23:10 pm    Post subject:

magoseitor wrote:
Ok, the MOD file is supposed to be samples+structure... we take the samples, and the structure, rearrange it to whatever the 89Ti likes, making a new ti-readable file.

There’s hardly anything to rearrange apart from throwing away the unnecessary song title and sample names. The patterns and samples are sitting in the file uncompressed, so the best thing you can do is leave them alone. Well, you might substitute the pitch values (which are related to Amiga hardware where this format was conceived) with note identifiers and thus reunite the lower and upper 4 bits of the sample identifier to make data easier to parse, but that’s no major transformation.

magoseitor wrote:
We make a new player that do the same as the mod players: throw out the samples according to the structure, plus, some effects.

I’m not sure about the possibilities on 68k models, but it might not be possible to produce continuous sound while also doing something else. You should consult a 68k hacker, but I’m not sure any regular on this forum counts as such.
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magoseitor


Newbie


Joined: 17 Feb 2008
Posts: 8

Posted: 11 Mar 2008 08:57:37 pm    Post subject:

Well,.. after reading the mod format and the midi format i guess i still need plenty more C/asm knowledge. I'll first try to output a simple 12k WAV PCM enconded file to test the possible hardware i might build. If the simple data stream plays with aceptable quality (at least form my point of view) with the external hardware, the i get into the software part.

thanks for the answers... Smile
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CoBB


Active Member


Joined: 30 Jun 2003
Posts: 720

Posted: 12 Mar 2008 01:26:26 am    Post subject:

magoseitor wrote:
Well,.. after reading the mod format and the midi format i guess i still need plenty more C/asm knowledge.

Forget midi, that’s completely out of the question without appropriate sound hardware to render it. Modules can work. By the way, the format descriptions don’t really mention implementation details for the effects, which I learned the hard way while writing my own player long ago...
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magoseitor


Newbie


Joined: 17 Feb 2008
Posts: 8

Posted: 13 Mar 2008 06:04:08 pm    Post subject:

Thanks for pointing that out, i like more mod than midi.. just spoke about mod for saying another pre-sampled file format.

About the hardware, i think something about this..

89Ti I/O port (series data stream) -> 74HC164N (8-Bit Serial-to-Parallel Shift Register) -> 8 AND gates -> 8-bit DAC

Know... i still have doubts about DAC's. What kind of binary number are these devices used to operate with? (signed, unsigned, ones or twos complement??)
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Jim e


Advanced Member


Joined: 05 Sep 2005
Posts: 360

Posted: 16 Mar 2008 10:12:25 pm    Post subject:

Just for your info, the 89 has Ti-vibe. Pretty much realsound for the 89. To bad they can't make their own flash apps.

http://www.ticalc.org/archives/files/fileinfo/386/38629.html
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magicdanw
pcGuru()


Calc Guru


Joined: 14 Feb 2007
Posts: 1110

Posted: 16 Mar 2008 10:21:01 pm    Post subject:

Jim e wrote:
To bad they can't make their own flash apps.[post="121563"]<{POST_SNAPBACK}>[/post]
Are you sure about that?
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Jim e


Advanced Member


Joined: 05 Sep 2005
Posts: 360

Posted: 16 Mar 2008 10:36:40 pm    Post subject:

magicdanw wrote:
Jim e wrote:
To bad they can't make their own flash apps.[post="121563"]<{POST_SNAPBACK}>[/post]
Are you sure about that?
[post="121564"]<{POST_SNAPBACK}>[/post]

Yes, they don't have a key to sign their apps.
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Jacoby


Newbie


Joined: 10 Mar 2008
Posts: 9

Posted: 17 Mar 2008 05:57:18 am    Post subject:

magoseitor wrote:
Know... i still have doubts about DAC's. What kind of binary number are these devices used to operate with? (signed, unsigned, ones or twos complement??)
[post="121457"]<{POST_SNAPBACK}>[/post]


They do exactly what they say on the tin. They give you a voltage output that represents the value of a binary code given to them. The bit length of that binary value depends upon the DAC you choose. You need to feed raw, uncompressed mono audio data into the DAC unless you have some sort of a decoder in the DAC as well (see my above link to an MP3 decoder chip).
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