User Guide

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GM500-U1G_A
Hardware Development Guide
2.8. USIM Card Interface
2.8.1. Description of USIM pins
The USIM card interface circuitry meets ETSI and IMT-2000 SIM interface requirements. Both 1.8V and 3.0V USIM cards are
supported.
Table 2-8Pin Definition of the USIM Interface
Pin Name Pin NO. I/O Description Comment
USIM1_VCC 40 PO Power supply for USIM1 card Either 1.8V or 3V is supported by the module automatically
USIM1_DATA 38 IO Data signal of USIM1 card Pull-up to USIM1_VCC with 10k resistor internally
USIM1_CLK 37 DO Clock signal of USIM1 card
USIM1_RST 39 DO Reset signal of USIM1 card
USIM1_DETECT 41 DI USIM1 card hot swap detection pin. 1.8V power domain. The signal is internally pulled up.
Keep USIM1_DETECTnot connected, if it is not used.When USIM
detect function is enable (send AT command AT+ZSDT=1), and if
it is Low, USIM is present; if it is High, USIM is absent.
GND 36 Ground
The following figure shows the reference design of the 8-pin USIM card.