Nintendo 1504166 - Game Boy Advance SP Edition Console Programming Manual page 89

AGB Programming Manual
SOUND1CNT_H [d10 - 08] Number of Envelope Steps
Sets the length of each step of envelope amplification or attenuation.
With n the specified value, the length of 1 step (steptime) is determined by
the following formula.
When n = 0, the envelope function is turned off.
SOUND1CNT_H [d07 - 06] Waveform Duty Cycle
Specifies the proportion of amplitude peaks for the waveform.
Setting
00
01
10
11
SOUND1CNT_H [d05 - 00] Sound Length
With st signifying the sound length, the length of the output sound is
determined by the following formula.
©1999 - 2001 Nintendo of America Inc.
1
steptime n
64
Duty Cycle
12.5%
25.0%
50.0%
75.0%
time ( 64 st )
256
89
(sec)
Waveform
1
(sec)
Sound
D.C.N. AGB-06-0001-002B4