Nintendo 1504166 Programming Manual - Page 98

SOUND4CNT_H [d07 - 04] Polynomial Counter Shift Clock Frequency Selection, frequency, ratio, dividing

Page 98 highlights

AGB Programming Manual Sound Address 07Ch Register SOUND4 CNT_H 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00 Attributes NR44 NR43 R/W Initial Value 0000h Sound Length Flag 0: Continuous 1: Counter Initialization Dividing Ratio Freq. Selection Polynomial Counter Step Number Selection 0: 15 steps 1: 7 steps Polynomial Counter Shift Clock Freq. Selection SOUND4CNT_H [d15] Initialization Flag A setting of 1 causes Sound 4 to be restarted. SOUND4CNT_H [d14] Sound Length Continuous sound output with 0; with 1, sound output only for the time specified in the sound length data of NR41. When sound output ends, the Sound 4 ON flag of NR52 is reset. SOUND4CNT_H [d07 - 04] Polynomial Counter Shift Clock Frequency Selection With n signifying the specified value, the shift clock frequency (shiftfreq) is selected as shown in the following formula. shiftfreq = dividing ratio frequency × 1 2 ( n+1) However, %1110 and %1111 are prohibited codes. SOUND4CNT_H [d03] Polynomial Counter Step Number Selection A value of 0 selects 15 steps; 1 selects 7 steps. ©1999 - 2001 Nintendo of America Inc. 98 D.C.N. AGB-06-0001-002B4

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AGB Programming Manual
Sound
©1999 - 2001 Nintendo of America Inc.
98
D.C.N. AGB-06-0001-002B4
15
14
13
12
11
10
09
08
07
06
05
04
03
02
01
00
SOUND4
CNT_H
07Ch
0000h
R/W
Address
Register
Attributes
Initial Value
NR43
NR44
Dividing Ratio Freq.
Selection
Polynomial Counter Shift
Clock Freq. Selection
Polynomial Counter Step
Number Selection
0: 15 steps
1: 7 steps
Sound Length Flag
0: Continuous
1: Counter
Initialization
SOUND4CNT_H [d15] Initialization Flag
A setting of 1 causes Sound 4 to be restarted.
SOUND4CNT_H [d14] Sound Length
Continuous sound output with 0; with 1, sound output only for the time
specified in the sound length data of NR41.
When sound output ends, the Sound 4 ON flag of NR52 is reset.
SOUND4CNT_H [d07 - 04] Polynomial Counter Shift Clock Frequency Selection
With n signifying the specified value, the shift clock frequency (shiftfreq) is
selected as shown in the following formula.
)
1
(
2
1
frequency
ratio
dividing
×
=
n
shiftfreq
However, %1110 and %1111 are prohibited codes.
SOUND4CNT_H [d03] Polynomial Counter Step Number Selection
A value of 0 selects 15 steps; 1 selects 7 steps.