Figure 62 - Game Boy Advance Sound System Block Diagram - Nintendo GAME BOY ADVANCE Programming Manual

May 25, 2005
10 Sound
In addition to 4 channels of CGB-compatible sound, Game Boy Advance has 2 channels of direct sound.
1. Direct Sounds A and B
• Provides playback of linear 8-bit audio data.
• Uses the timer and DMA.
2. Sound 1
Allows generation of rectangular waveforms with sweep (frequency change) and envelope (volume
change) functions.
3. Sound 2
Allows generation of rectangular waveforms with envelope functions.
4. Sound 3
• Allows playback of any waveform recorded in waveform RAM.
• Waveform RAM in Game Boy Advance has double the capacity of that in CGB.
5. Sound 4
Can generate white noise with the envelope function.
The synthesis ratio of sounds 1-4 to direct sound can be specified.
10.1 Sound Block Diagram

Figure 62 - Game Boy Advance Sound System Block Diagram

Sound 1
Sound 2
Sound 3
Sound 4
Direct Sound A
DMA1
Direct Sound B
DMA2
10.2 Direct Sounds A and B
Direct sounds have 2 channels, A and B. Linear 8-bit audio data can be played back.
The audio data are set to a bias level of 00h and are 8-bit data (+127 to -128), obtained by 2's complement.
Audio data are transferred sequenti ally to the sound FIFO (8-word capacity), using the sound FIFO trans-
fer mode of DMA 1 and 2.
The sampling rate can be set to an arbitrary value using timers 0 and 1.
© 1999-2005 NINTENDO
4 9bit
→
R/L
4 9bit
→
Selection
&
4 9bit
→
Addition
4 9bit
→
FIFO A
8 9bit
→
(8 Words)
FIFO B
8 9bit
→
(8 Words)
1-Fold
/
2-Fold
/
4-Fold
R/L
Selection
&
Addition
1-Fold/2-Fold
1-Fold/2-Fold
AGB-06-0001-002-B13
Released: May 27, 2005
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