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TIA Music on Atari 7800, (Stella's Stocking/ Mappy)

music 7800 tia

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#1 R_Leo_1 OFFLINE  

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    Star Raider

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Posted Wed Feb 27, 2019 9:39 PM

Howdy all. So after hearing the amazing music on the Stella's Stocking and Mappy carts, I was wondering how that was done and if that programming wizardry would be possible on the 7800. I think it would be a great way to improve the quality of the 7800 sounds, without requiring an extra chip on the cart.



#2 RevEng OFFLINE  

RevEng

    Bit Player

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Posted Wed Feb 27, 2019 10:16 PM

Mappy is using a softsynth technique. The ARM CPU in the cart is running the synth algorithm, and it passes sample playback values to the 6507, which has to update TIA with them every single scanline, even when the screen is not being displayed.

Stella's Stocking is doing something similar without the ARM chip, but due to the lack of hardware assistance, it can only play music during the title screen.

The 7800 could do this too, but it would tie the hands of the 6502, and we'd still be requiring an extra (much more difficult to solder) ARM chip on cart, or be stuck with no free time to do anything interesting during playback.

Since the 7800 has an audio pin on the cartridge port (unlike the 2600) it's better to just use an independent sound chip, and not tie the hands of the 6502. Or use techniques that make TIA sound more in tune.

#3 Heaven/TQA OFFLINE  

Heaven/TQA

    Quadrunner

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Posted Thu Feb 28, 2019 10:23 AM

I recommend TIA Tracker on PC



#4 R_Leo_1 OFFLINE  

R_Leo_1

    Star Raider

  • Topic Starter
  • 98 posts
  • Location:Davenport, FL

Posted Thu Feb 28, 2019 11:32 AM

Mappy is using a softsynth technique. The ARM CPU in the cart is running the synth algorithm, and it passes sample playback values to the 6507, which has to update TIA with them every single scanline, even when the screen is not being displayed.

Stella's Stocking is doing something similar without the ARM chip, but due to the lack of hardware assistance, it can only play music during the title screen.

The 7800 could do this too, but it would tie the hands of the 6502, and we'd still be requiring an extra (much more difficult to solder) ARM chip on cart, or be stuck with no free time to do anything interesting during playback.

Since the 7800 has an audio pin on the cartridge port (unlike the 2600) it's better to just use an independent sound chip, and not tie the hands of the 6502. Or use techniques that make TIA sound more in tune.

 

Ah okay, thanks so much for the detailed explanation! 

 

I recommend TIA Tracker on PC

 

I actually have TIA Tracker but I keep having issues with notes being delayed and not being played on beat.







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