msm7630 Oki Semiconductor, msm7630 Datasheet - Page 91

• Manufacturer Part Number: msm7630
• Description: Universal Speech Processor
• Manufacturer: Oki Semiconductor

¡ Semiconductor
4. Speech Output Registers Address Configuration
The addresses used by the speech output registers/circuits are assigned at 0x80000000. Accesses to
this space will be 3t access.
Speech Output
1. Output Waveform from DAO1
The speech output pin directly outputs the output of the DA converter.
The output waveform from DAO1 will be a staircase synchronized to the sampling frequency.
Maximum output amplitude will be (4095/4096 ¥ V
2. Output Filter
Because the output from DAO1 is a staircase described above, add a low-pass filter. The diagram
below shows a reference circuit for a Butterworth low-pass filter.
2
3
–
+
8
1k
1
R
1000p
MC14573P
Speech Output Register 1
Speech Output Register 2
D/A Conversion Register
Status Register
General Register
MSM7576 Mode Select Register
R
1200p
300p
R
R = 47k, f = 4.8 kHz (95 model: for 12 kHz sampling)
R = 36k, f = 6.4 kHz (96 model: for 16 kHz sampling)
R = 27k, f = 9.6 kHz (97 model: for 22 kHz sampling)
15
14 +
–
Butterworth low-pass filter
13
0.1µ
4
16
R
2200p
DD
220p
0x80000000
0x80000004
0x80000008
0x8000000C
0x80000010
0x80000020
R
).
11
12 +
–
9
10
1k
6
5 +
–
MSM7630
7
91/95