Application notes
Version 8 dated 15.03.00 200
Siemens Information and Communication Products
A
8.8.5 Adding echo suppression functionality
Fig. 8-8 Handsfree application diagram
The example depicted above makes use of the M20 internal voiceband codec. The M20 is controlled by the HOST via the
AT commands. The HOST is also responsible for booting and controlling the handsfree DSP. If an external voiceband
codec is to be used, the serial link between the DSP and the internal codec (VSFS_C, VSCLK_C, VSDI_C, VSDO_C)
must be omitted and the external codec has to be linked to the DSP.
Note
: External clock signalling is not possible in this configuration.
A handsfree DSP can be ordered, for example, from Analog Devices: AD2186L. For further information please contact
Analog Devices (http://www.analog.com/).
8.8.6 Ignition line
Fig. 8-9 Ignition line
69
68
67
66
12
13
14
15
VSFS_V
VSCLK_V
VSDI_V
VSDO_V
VSCLK_C
VSDI_C
VSDO_C
SFS1
SCLK1
SDO1
SDI1
SFS2
SCLK2
SDO2
SDI2
M20
DSP
39 42
M ICPM ICN
40 41
SPP
SPN
10 72
USCTX_
USCRX_
HOST
AT-Commands
Host-Interface
VSFS_C
GN D
From Power supply
Implement as shown
Power supply: 8-24V
80 pole SMD Connector:
Power supply DC IN: 6V
Pins:
DC IN(6V): 18-22, 58-62
IGNITION: 8
GND: 17, 23-25, 38, 43, 56
57, 63-65
To M2 0 T
When using M20T When using M20
1
1
4
6
4
+
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