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L850-GL Hardware User Manual Page 35 of 54
angle routing should be avoided.
The two pairs differential signal lines should be routed on the layer that is adjacent to the ground
layer, and wrapped with GND vertically and horizontally.
3.5 USIM Interface
The L850 module has a built-in USIM card interface, which supports 1.8V and 3V SIM cards.
3.5.1 USIM Pins
The USIM pins description as shown in the following table:
Pin Pin Name
I/O Reset Value Description
Type
36
UIM_PWR
PO -
USIM power supply
1.8V/3V
30
UIM_RESET
O
L
USIM reset
1.8V/3V
32
UIM_CLK
O
L
USIM clock
1.8V/3V
34
UIM_DATA
I/O L
USIM data, internal pull up(4.7KΩ)
1.8V/3V
66
SIM_DETECT
I
PD
USIM card detect, internal 390K
pull-up.
Active high, and high level indicates
SIM card is inserted; and low level
indicates SIM card is detached.
1.8V
3.5.2 USIM Interface Circuit
3.5.2.1 N.C. SIM Card Slot
The reference circuit design for N.C. (Normally Closed) SIM card slot is shown in Figure 3-16: