u-blox LEON-G100 ECALL, Руководство по системной интеграции

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LEON-G100 / LEON-G200 - System Integration Manual
GSM.G1-HW-09002-G3 Preliminary System description
Page 63 of 125
Figure 37 shows an application circuit connecting a headset (with a 2.2 k Ω electret microphone and a 32 Ω
receiver) to the LEON-G100 / LEON-G200 modules. Pin 2 & 5 are shorted in the headset connector, causing
HS_DET
to be pulled low. When the headset plug is inserted
HS_DET
is pulled up internally by the module,
causing a rising edge for detection.
Perform the following steps on the application board (as shown in Figure 37; the list of components to be
mounted is shown in Table 23):

Mount a series capacitor on the
HS_P
line to decouple the bias. 10 µF ceramic capacitor (e.g. Murata
GRM188R60J106M) is required if a 32 Ω receiver or a load with greater impedance (as a single ended
analog input of a codec) is connected to the line. 22 µF series capacitor (e.g. Murata GRM21BR60J226M) is
required if a 16
Ω receiver is connected to the line

Mount a 82 nH series inductor (e.g. Murata LQG15HS82NJ02) on each microphone line, and a 27 pF bypass
capacitor (e.g. Murata GRM1555C1H270J) on all audio lines to minimize RF coupling and the TDMA noise
LEON-G100 /
LEON-G200
C4
AUDIO HEADSET
CONNECTOR
C1 C2 C3
J1
2
5
3
4
6
1 L1
L2
18
HS_DET
37
HS_P
42
MIC_GND2
41
MIC_BIAS2
D1
Figure 37: Headset mode application circuit
Reference Description Part Number - Manufacturer
C1, C2, C3 27 pF Capacitor Ceramic COG 0402 5% 25 V GRM1555C1H270JZ01 - Murata
C4 10 µF Capacitor Ceramic X5R 0603 20% 6.3V GRM188R60J106M - Murata
L1, L2 82nH Multilayer inductor 0402
(self resonance frequency ~1 GHz) LQG15HS82NJ02 - Murata
J1 Audio Headset 2.5 mm Jack Connector SJ1-42535TS-SMT - CUI, Inc.
D1 Varistor Array for ESD protection CA05P4S14THSG - EPCOS
Table 23: Example of components for headset jack connection
1.10.1.5 Hands-free mode
Hands-free mode can be implemented using a loudspeaker and a dedicated microphone.
Hands-free functionality is implemented using appropriate DSP algorithms for voice-band handling (echo
canceller and automatic gain control), managed via software (Refer to
u-blox AT Commands Manual [2];
AT+UHFP command).
In this mode the main downlink audio path must be “Loudspeaker”, the main uplink audio path can be
“Handset microphone” or “Headset microphone” (refer to
u-blox AT Commands Manual [2]; AT+USPM
command: <main_uplink>, <main_downlink> parameters). Use of an uplink audio path for hands-free makes it
unavailable for another device (handset/headset). Therefore:

Microphone can be connected to the input pins MIC_BIAS1 / MIC_GND1 or MIC_BIAS2 / MIC_GND2

High power loudspeaker must be connected to the output pins SPK_P / SPK_N