Headset; Figure 9-44 Headset Circuit Block Diagram - Huawei U8815 Maintenance Manual

U8815
Maintenance Manual
Signal
SND_MICBIAS

9.4.5 Headset

Figure 9-44 shows the headset circuit block diagram.

Figure 9-44 Headset circuit block diagram


The headset connect status is identified according to the HS_DETECT_N (GPIO_026).
Before connecting the headset, HS_DETECT_N is pulled up to high level by VREG_S3.
After connecting the headset, HS_DETECT_N is dropped down to low level.
The headset MIC is supplied with power by MIC_BIAS1 (PM8029/HSED_BIAS1), and it is
used for headset answer detection.
The headset of the U8815 is compatible with two line sequences. The iphone's headset line
sequence is compatible by default. The pull-up voltage is L19 2.6 V.

Failure: No sound can be heard from the headset.
Solution: Replace the headset or the headset connector.
Figure 9-45 shows the troubleshooting process for no sound from the headset failure.
Issue 1.0 (2012-02-13)
Description
Bias voltage of the secondary microphone
Analysis
Troubleshooting Process
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Copyright © Huawei Technologies Co., Ltd.
9 Principles and Failure Analysis
Reference
Measurement or
Wave Form
None
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