Touch Screen - LG KT878 Service Manual

VBAT AP_VCC_2V8 AP_VCC_2V8
FB806 FB807
BLM15AB601SN1 BLM15AB601SN1
FB808
FB809
AP_CLK_POUT
AP_AC97_RESETB
AP_AC97_BITCLK
AP_AC97_SYNC
AP_AC97_SDATAOUT
AP_AC97_SDATAIN
AP_CODEC_IRQ
R822 47
X_P
R823 47
Y _P
R824 47
X_N
R825 47
Y _N
C821
0.01u

3.7 Touch Screen

触摸屏原理
KT878 采用的是四线式电阻触摸原理，在 WM9713 内部数模转换之后，通过 AC'97 传
到 PXA310 进行定位识别处理。
AP_VCC_2V8
R804
0
U802
9
DCVDD
R806 0 1
DBVDD
BLM15AB601SN1 13
TPVDD
BLM15AB601SN1 25
AVDD
43
HPVDD
38
SPKVDD
R812 0 2
MCLKA
3
MCLKB/GPIO6/ADA/MASK
AP_AC801 11
RESETB/GPIO7/PENDOWN
AP_AC802 6
BITCLK
AP_AC803 10
SY NC
AP_AV804 5
SDATAOUT
AP_AC805 8
SDATAIN
AP_AC806 45
GPIO2/IRQ
44
GPIO1/PCMCLK
46
GPIO3/PENDOWN/PCMFS
47
GPIO4/ADA/MASK/PCMDAC
48
GPIO5/SPDIF/PCMADC
14
X+
15
Y+
16
X-
17
Y-
12
WIPER/AUX4/GPIO8/SPDIF
C822 C823 C824
WM9713
0.01u 0.01u 0.01u
图 3-35 WM9713 原理图
R822 47
X_P
R823 47
Y _P
R824 47
X_N
R825 47
Y _N
C821
0.01u
- 42 -
29 C838 1u
HEADPHONE_MIC_CODEC_P
MIC2A/COMP1/AUX1
30 TP805
MIC2B/COMP2/AUX2
31 TP801
MONO
28 C839 1u
MICPHONE_CODEC_P
MICBIAS
21
MIC1
22 C840 1u
MICCM
23
LINEL
24
LINER
19
PCBEEP
20
MONOIN
33 TP803
OUT4
39
HPL
41
HPR
35
SPKL
36
SPKR
37 TP804
OUT3
27
VREF
32
CAP2
4
DGND1
18
TPGND
26
AGND
42 C818 C819
AGND2
40
HPGND
7 4.7U 4.7U
DGND2
34
SPKGND
C822 C823 C824
0.01u 0.01u 0.01u
3. 技术综述
C811 1u
C812 1u
C813 1u
C814 1u
C815 FB801 BLM15AB601SN1
33u
C816 FB802 BLM15AB601SN1
33u R816 0
R818 0
X+
Y+
x_
y_
FM_AUDIO_L
FM_AUDIO_R
HANDPHONE_R
HANDPHONE_L
HP_L
HP_R
SPKL
SPKR