Huawei EM770 - Page 25

HUAWEI EM770 HSPA PC Embedded Module V100R001
Product Specification
Issue 1
(2008-09-15)
Huawei Confidential: This documents is Huawei Proprietary and Confidential(NDA
Required).It may not be duplicated, neither distributed externally without
prior and written permission of Huawei.
Page
25 of 68
Design guide
The USIM signals are connected to the Mini PCI Express card connector (the card
edge connector) and pass through an EMI filtering and ESD protection circuit on the
module board before entering the EM770 processor. There is also an EMI filtering
and ESD protection circuit between SIM card interface and Mini PCI interface on the
user’s board.
1. Power supply
The SIM interface is powered by an LDO regulator. The default value of this regulator
is 2.85 V. The power of the regulator is programmable in the range of 1.5 V to 3.05 V
and is expected to be set to 3.0 V or 1.8 V.
2. Modem signals
After a power-on or reset, the USIM signals are activated to detect if a SIM card is
present and to initialize it if it exists. Once a card has been detected and initialized,
the interface is always on. However, the clock signal is only activated when data is
actually being transferred. The USIM signals from the MSM are connected to the
level translators and then to the Mini Card host connector.
These levels exceed those required in ISO/IEC 7816-3.
3. SIM signals
The following data is taken from ETSI standard Specification of the 3 Volt Subscriber
Identity Module - Mobile Equipment (SIM-ME) interface (GSM 11.12 version 4.3.1).
Table 3-7 SIM RST requirements
RST Minimum Maximum
V
IL
0 0.2Vcc
V
IH
0.7Vcc Vcc
Table 3-8 SIM CLK requirements
CLK Minimum Maximum
V
IL
0 0.2Vcc
V
IH
0.7Vcc Vcc
Table 3-9 SIM IO requirements
IO Minimum Maximum
V
IL
0 0.4
V
IH
0.7Vcc Vcc
V
OL
–0.3 0.2Vcc
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