Huawei Ascend - SIM Card

Y210 Mobile Phone
Maintenance Manual
9 Principles and Failure Analysis
Issue 1.0 (2012-11-28)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
58
used to guide light from the LEDs to the touch key area. Table 9-17 describes the interfaces
between the touch panel, MSM7225A, and PM8029.
Table 9-17 Interfaces between touch panel, MSM7225A, and PM8029
Touch Panel
Interface
Pin
Description
VDD_2V8_TP
VREG_L12_2P85
(PM8029)
Touch panel analog power supply, 2.85 V
VREG_S3
VREG_S3 (PM8029)
Touch panel digital power supply and I/O
connector power supply, 1.8 V
TOUCH_INT
GPIO_82
(MSM7225A)
Touch panel interrupt signal
I2C1_SCL
GPIO_131
(MSM7225A)
Touch panel's I2C clock
I2C1_SDA
GPIO_132
(MSM7225A)
Touch panel's I2C data
TOUCH_RST_N
GPIO_96
(MSM7225A)
Touch panel reset signal
9.4.15 SIM Card
The MSM7225A is not compatible with the SIM card interface. The PM8029's MPP pins are
used to convert voltage levels of the signals for communication between the MSM7225A and
the SIM card.
The voltage of VREG_L16_UIM1 can be set to 1.5–3.05 V. The USIM interface's operating
voltage is usually 1.8 V or 3.0 V. Table 9-18 describes the voltage level conversion interface
of the PM8029.
Table 9-18 Voltage level conversion interface of the PM8029
Signal for Interfacing
with the MSM
Voltage
Level
Signal for Interfacing
with the USIM Card
Voltage Level
-
VREG_S3
UIM1_RESET
VREG_L16_UIM1
(configured by the
phone's firmware)
UIM1_MSM_CLK
UIM1_CLK
UIM1_MSM_DATA
UIM1_DATA
Considering that SIM card operations are frequent, transient-voltage-suppression (TVS) diodes are
added to the circuit to provide ESD and surge protection.