adsp-bf527c Analog Devices, Inc., adsp-bf527c Datasheet - Page 14

• Manufacturer Part Number: adsp-bf527c
• Description: Blackfin Embedded Processor
• Manufacturer: Analog Devices, Inc.

ADSP-BF523C/ADSP-BF525C/ADSP-BF527C
Sidetone Mode
The sidetone mode routs the microphone input to the line and
headphone outputs as shown in
The sidetone mode allows the microphone input to be attenu-
ated to the outputs for telephone and headset applications.
The sidetone mode and attenuation are selected under software
control using the SIDETONE bit as shown in
sidetone the output from the DAC (DACSEL) and line inputs
(BYPASS) should be deselected from the line output block.
However, this can also be used to sum the DAC output, line
inputs and microphone inputs together. The microphone boost
gain control and headphone output volume control and mutes
are still operational in sidetone mode. To avoid distortion the
MICIN
10 K
VMID
-
+
50 K
Figure
17.
VMID
10DB GAIN BOOST
Table
-
+
Rev. PrC | Page 14 of 44 | June 2008
9. In true
FROM
LINE
INPUTS
FROM
DAC
Figure 17. Sidetone Mode
DACSEL (OFF)
BYPASS (OFF)
SIDETONE (ON)
maximum signal at any point in the sidetone path must be no
greater than 1.0 V(rms) at AVDD = 3.3V. This level tracks
directly with AVDD.
Table 9. Sidetone Mode Control
Register
Address
000 0100 5
VMID
Bit Label
7:6 SIDEATT[1:0] 00
+
-
SIDETONE
Preliminary Technical Data
VMID
Default Description
0
LINEOUT
+
-
Sidetone Switch (analog)
1 = Enable Side Tone
0 = Disable Side Tone
Sidetone Attenuation
11 = –15 dB
10 = –12 dB
01 = –9 dB
00 = –6 dB
HPOUT