U8185
Maintenance Manual
9 Principles and Failure Analysis
Issue 1.0 (2012-03-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
50
Signal
Description
Reference Measurement or
Wave Form
CABC
Content adaptation brightness control
None.
LCDC_ENABLE
Data enable
None.
LCDC_PCLK
Dot clock signal
None.
LCDC_HSYNC
Hor izontal synchronization signal
None.
LCDC_VSYNC
Vertical synchronization signal
None.
LCD_ID0/LCD_ID1
LCD_ID0 and LCD_ID1 are LCD's
vendor indicators.
00 indicates that the LCD is from
TRULY.
11 indicates that the LCD is from
BYD. In this case, the software
can call LCD initiation programs
for different LCDs.
LED+
LED anode
None.
LED_K1/LED_K2/LED_K3/
LED_K4/
LED cathode
None.
VREG_L12_2P85
Supplies power to the analog section.
None.
VREG_S3
Supplies power to the I/O port circuit.
None.
9.4.2 Keypad
Circuit Schematic Diagram
Figure 9-14
Power key