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S-DSP: Difference between revisions

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(page 3-7-1 of Book II)
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The '''S-DSP''' is the digital signal processor.  It produces audio for the [[DAC]] and is controlled by the [[S-SMP]].  It is clocked by [[X2]].
The '''S-DSP''' is the digital signal processor.  It produces audio for the [[DAC]] and is controlled by the [[S-SMP]].  It is clocked by [[X2]].


It has 128 registers (DSPRAM) that can be manipulated by the S-SMP, some of which serve no hard-wired purpose and can be used as general-purpose RAM.  Some of them are:
It has 128 registers (DSPRAM) that can be manipulated by the S-SMP, some of which serve no hard-wired purpose and can be used as general-purpose RAM.  Registers with a ∴ before their name are written to by the S-DSP itself during active processing.  Here are some of 128:


{| class="wikitable"
{| class="wikitable"
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| 07 || GAIN
| 07 || GAIN
|-
|-
| 08 || ENVX
| 08 || ∴ENVX
|-
|-
| 09 || OUTX
| 09 || ∴OUTX
|-
|-
|  ||  
|  ||  
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| 6C || FLG
| 6C || FLG
|-
|-
| 7C || ENDX
| 7C || ∴ENDX
|-
|-
| 0D || EFB
| 0D || EFB

Revision as of 03:37, 18 December 2023

S-DSP in region D4 of the jwdonal schematic

The S-DSP is the digital signal processor. It produces audio for the DAC and is controlled by the S-SMP. It is clocked by X2.

It has 128 registers (DSPRAM) that can be manipulated by the S-SMP, some of which serve no hard-wired purpose and can be used as general-purpose RAM. Registers with a ∴ before their name are written to by the S-DSP itself during active processing. Here are some of 128:

Address Register
00 VOL (L)
01 VOL (R)
02 P (L)
03 P (H)
04 SRCN
05 ADSR (1)
06 ADSR (2)
07 GAIN
08 ∴ENVX
09 ∴OUTX
0C MVOL (L)
1C MVOL (R)
2C EVOL (L)
3C EVOL (R)
4C KON
5C KOF
6C FLG
7C ∴ENDX
0D EFB
1D ---
2D PMON
3D NON
4D EON
5D DIR
6D ESA
7D EDL
xE ---

The highest sound frequency that the S-DSP can produce is 16kHz, because of the 32kHz rate that sample-points are output. [1]

References

  1. https://problemkaputt.de/fullsnes.htm#snesapudspbrrpitch
  2. page 3-7-1 of Book II of the official Super Nintendo development manual