User's Manual

UMTS/HSPA Module Series
UC20 User Manual
UC20_Hardware_Design Confidential / Released 43 / 84
USIM_CLK
16
DO
Clock signal of USIM card.
USIM_RST
17
DO
Reset signal of USIM card.
USIM_PRES
ENCE
13
DI
USIM card insertion detection.
1.8V power domain.
USIM_GND
10
Specified ground for USIM card.
The following figure shows the reference design of the 8-pin USIM card.
Module
USIM_VDD
USIM_GND
USIM_RST
USIM_CLK
USIM_DATA
USIM_PRESENCE
22R
22R
22R
VDD_EXT
51K
100nF USIM Connector
GND
GND
33pF
33pF 33pF
VCC
RST
CLK
IO
VPP
GND
GND
USIM_VDD
15K
Figure 22: Reference Circuit of the 8 Pin USIM Card
Some AT commands are invalid when USIM card is not applied.
UC20 supports USIM card hot-plugging via the USIM_PRESENCE pin. For details, refer to document [1]
about the command AT+QSIMDET. If you do not need the USIM card detection function, keep
USIM_PRESENCE unconnected. The reference circuit for using a 6-pin USIM card connector is
illustrated as the following figure.
NOTE