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Additional audio possible?


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#1 cbmeeks OFFLINE  

cbmeeks

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Posted Mon Jan 7, 2019 3:46 PM

So, I was wondering...is it possible for a TI cartridge to have an additional audio chip like the Famicom games did?  I found a cartridge pinout but didn't see any pins for audio.

 

But I vaguely remember someone connecting a SID chip to a TI a long time ago.  Was that through the side expansion?

 

Finally, does anyone know why some type of audio expansion (other than speech) hasn't caught on like the F18a?  The beauty of the F18a is that it's a standard as well as enhanced video.  Seems like something for audio would be desirable as well.

 

I've recently designed my own 6502 computer (and had boards made) so I guess I'm looking for an excuse to start a new project.  :-)

 

Thanks



#2 arcadeshopper ONLINE  

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Posted Mon Jan 7, 2019 3:55 PM

So, I was wondering...is it possible for a TI cartridge to have an additional audio chip like the Famicom games did?  I found a cartridge pinout but didn't see any pins for audio.

 

But I vaguely remember someone connecting a SID chip to a TI a long time ago.  Was that through the side expansion?

 

Finally, does anyone know why some type of audio expansion (other than speech) hasn't caught on like the F18a?  The beauty of the F18a is that it's a standard as well as enhanced video.  Seems like something for audio would be desirable as well.

 

I've recently designed my own 6502 computer (and had boards made) so I guess I'm looking for an excuse to start a new project.  :-)

 

Thanks

 

Cart no,  sidecar or pbox card, yes.. but only if the speech isn't installed or has been modified, as it doesn't pass through the audio line.

 

Sidmaster99 is a peb card, works great! Except for the best SID music is written in 6510assy so we get some, but not all of the good stuff 

http://www.dsapsc.com/what-is-sid.html

 

FourTI card was also a peb card.. adds 4 sound chips (same ones as in the console) for quadraphonic ti goodness.. 

http://www.unige.ch/.../ti99/forti.htm

 

I have the sidmaster it's mostly idle ..played some songs and then its not that useful suppose game designers could detect and support it..but ram is precious!  

 

Greg



#3 --- Ω --- OFFLINE  

--- Ω ---

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Posted Mon Jan 7, 2019 3:58 PM

The beauty of the F18a is that it's a standard as well as enhanced video.  Seems like something for audio would be desirable as well.

 

That's a freaking BRILLIANT idea!  Something that would look and act the same to the TI in normal mode, but if there was a 'software trigger/toggle' in a program, it would switch to enhanced mode.

I don't recall if the TI's audio chip is in a socket though,  if not it wouldn't be as plug and play as the F18A.



#4 FarmerPotato ONLINE  

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Posted Mon Jan 7, 2019 4:22 PM

There is no sound out from the 34 pin cartridge port, though nothing prevents a cartridge from packing an extra memory-mapped device like a sound chip. 

The side port has an AUDIO IN though. Speech and MBX are the only peripherals to use it AFAIK.

 

There was Marc Hull's Sid Master, a card for the Pbox. (last produced 2005 ish?)

There have been MIDI cards.

 

FORTI was a 1982 project by a TI engineer (Lee Cantwell?) which put 4 TI sound chips on one card.

 

I am working on FORTI-2 which will be a sidecar peripheral and offer unlimited stereo audio possibilities.

 

Like the original FORTI, its native language will be FORTH, but it will be accessible from any language, including access to 12 voices from BASIC.

 

You will be able to load waveforms from BASIC with the delightfully wacky format CALL SNDCHAR8(1, "01FF") (set voice 1 to a simple 8 bit sawtooth wave,  interpolated.) To put it back to a basic square wave, CALL SNDCHAR8(1, "01FF", 8)

 

I am testing with the free AKWF set downsampled to reasonable memory size for the 4A (they sound.. not as good).

As a bonus, AKWF has samples for a lot of 80s sound chips!

 

FORTI-2 also has its own SD card slot, so loading the samples by name should be a much better way to do it. Imagine CALL WAVE(1, "AKWF_0167.WAV")

 

The changes persist (FORTI-2 requires external power) so you can change the timbres and then play Parsec, for instance. (I'm using a sound list from Parsec in my testing.)

 

I have over 200 hours into this project in 2018. Mostly spent debugging (current bug has FORTI-2 occasionally disrupting a memory cycle, typically crashing the 4A.)


Edited by FarmerPotato, Mon Jan 7, 2019 4:23 PM.


#5 cbmeeks OFFLINE  

cbmeeks

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Posted Mon Jan 7, 2019 7:26 PM

Thanks for the information!

 

@FarmerPotato, it sounds like you are nearing a new sound card?

 

An idea I had was to make some type of small audio card that would sit between the TI and the speech module so that it could pass audio through from the speech.  Not sure how that would work.

As much as I love the TMS9919, I was thinking of using the YM3812 and maybe a CPLD for glue.  Plus a DAC.

 

But I'm curious about your FORTI-2.  I've tried Forth more times that I care to admit and I just can't wrap my head around it.  I'm more of a 6502/ASM coder.

 

Do you have more information on your project?



#6 Tursi OFFLINE  

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Posted Mon Jan 7, 2019 7:39 PM

I always wanted a new sound chip, but yeah, internal or side port.

 

I had a prototype in earlier builds of Classic99 that replaced the beep with waveforms. It worked quite well - the idea being that it would retrigger on frequency change or increase in volume. Those two tests were enough to make everything existing sound pretty decent (and standard 'beep boop' music suddenly sounded like piano or strings - Alpiner was a favorite of mine to listen to.)

 

The other changes I'd want are wider frequency response and more channels. ;) If you threw a bit of channel mixing you'd have a nice FM Synth. ;)



#7 FDOS OFFLINE  

FDOS

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Posted Tue Jan 8, 2019 12:59 PM

There is no sound out from the 34 pin cartridge port, though nothing prevents a cartridge from packing an extra memory-mapped device like a sound chip. 

The side port has an AUDIO IN though. Speech and MBX are the only peripherals to use it AFAIK.

 

There was Marc Hull's Sid Master, a card for the Pbox. (last produced 2005 ish?)

There have been MIDI cards.

 

FORTI was a 1982 project by a TI engineer (Lee Cantwell?) which put 4 TI sound chips on one card.

 

I am working on FORTI-2 which will be a sidecar peripheral and offer unlimited stereo audio possibilities.

 

Like the original FORTI, its native language will be FORTH, but it will be accessible from any language, including access to 12 voices from BASIC.

 

You will be able to load waveforms from BASIC with the delightfully wacky format CALL SNDCHAR8(1, "01FF") (set voice 1 to a simple 8 bit sawtooth wave,  interpolated.) To put it back to a basic square wave, CALL SNDCHAR8(1, "01FF", 8)

 

I am testing with the free AKWF set downsampled to reasonable memory size for the 4A (they sound.. not as good).

As a bonus, AKWF has samples for a lot of 80s sound chips!

 

FORTI-2 also has its own SD card slot, so loading the samples by name should be a much better way to do it. Imagine CALL WAVE(1, "AKWF_0167.WAV")

 

The changes persist (FORTI-2 requires external power) so you can change the timbres and then play Parsec, for instance. (I'm using a sound list from Parsec in my testing.)

 

I have over 200 hours into this project in 2018. Mostly spent debugging (current bug has FORTI-2 occasionally disrupting a memory cycle, typically crashing the 4A.)

 

Wow!  Excellent idea, as my first programming language was figForth, then TI Basic, then TI Forth, then TI Forth for MDOS, which I used to create Forth+ for the 9640 Geneve, and was released in early December 1993.  Never had more than 10 registered users.  However, I did start two other projects; X4th99 and TIB+ (TI Basic Plus) for the TI-99/4A, but stopped X4th99 to help Mark Wills with his TurboForth (add my X4th99 library system that uses up to 1MB of AMS/SAMS expansion memory).  This endeavor was well along (I had to learn F83, the basis for TurboForth first) in spite of my confusion due to a long history with figForth systems and now required to rewrite my library (less any already included in TurboForth) in the F83 dialect..  I've also ceased all efforts on TIB+ as it's no longer relevant due to so many other new advanced capabilities offered on AtariAge.  I'm in process of getting rid of two complete 9640 Geneve systems (one 2MB GenMOD & one PFM512K w/MEMEX), once I have everything fully functional for both systems.

 

Music is great for my depression and high blood pressure (which is why I also ceased all efforts in adding my library system to TurboForth).  I have lots on CD and SD, and 5.25" & 3.5" floppy diskettes for my TI/Geneve systems, including ForTI music, that I haven't been able to play for some time due to no free slot in my TI PEB because of work on the two Geneves and my SNUG TI-99/4P system.  I do hope you succeed in your development efforts for our TI-99/4A&P systems.

 

Good luck.

 

Bill






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