3.5 UART port
The module provides a UART port, the serial port level is 1.8V. The AT command can be sent
through the serial port, print program log information, etc. The module serial port supports
9600/19200/38400/57600/115200/230400bps baud rate and defaults is 115200bps.
PIN
Signal
I/O
Definition
11
UART_RX
DI
Sending data
13
UART_TX
DO
Receiving data
23
UART_CTS
DI
User enable module sending
25
UART_RTS
DO
Module requests the user to send
UART port design
Module serial port level is 1.8V, if the serial port needs to be connected with the MCU of 3.3V
level, it is necessary to add a level conversion chip to realize the matching, chip connection can
refer to the following design:
Level conversion circuit
3.6 USIM interface
The module provides a USIM card interface compatible with the ISO 7816-3 standard, and the
USIM card power supply is internally powered by the module. The source regulator provides
the voltage of 1.8V and 3.0V.
PIN
Signal
I/O
High level
Definition
6
USIM_DET
DI
1.8V
USIM hot plug detection
8
UIM_PWR
PO
1.8V/2.95V
USIM power
10
UIM_DATA
IO
1.8V/2.95V
USIM data
12
UIM_CLK
DO
1.8V/2.95V
USIM clock
14
UIM_RESET
DO
1.8V/2.95V
USIM reset
