5.11.1 UART1

Pin

 

Name

 

Direction

 

Function

 

 

 

 

 

 

 

32

 

DSR1

 

Output

 

Data Set Ready (UART1)

36

 

RI

 

Output

 

Ring Indicator

37

 

DTR1

 

Input

 

Data Terminal Ready (UART1)

38

 

DCD1

 

Output

 

Data Carrier Detect (UART1)

39

 

RTS1

 

Input

 

Ready To Send (UART1)

40

 

CTS1

 

Output

 

Clear To Send (UART1)

41

 

DTM1

 

Input

 

Data To Module from host (UART1)

42

 

DFM1

 

Output

 

Data From Module to host (UART1)

UART1 is a full featured Universal Asynchronous Receiver Transmitter providing full- duplex asynchronous communication.

UART1 has the following features:

•32 bytes of FIFO for both receive and transmit

•FIFO threshold interrupts

•1 start bit, 7 or 8 data bits, 1 optional parity bit, 1 or 2 stop bits

•Programmable baud rate

•Auto-configuration mode with auto-baud and auto-format operation

•Hardware flow control

•Software flow control.

UART1 signals replicate a 9-pin RS232 (V.24) serial port. However, UART1 signal levels are not compliant with the RS232 (V.28) standard. Conversion between the wireless modem CMOS levels and RS232 levels can be achieved using a standard interface IC, such as the Maxim Integrated Products MAX3237. The relationship between the levels is shown in the following table:

DTM, DFM

 

RI,RTS,CTS,DSR,DTM,DCD

 

RS232 level

 

GR64 level

 

 

 

 

 

 

 

1

 

OFF

 

<-3V

 

VREF-0.4V

0

 

ON

 

>+3V

 

0.4V

5.11.2 Serial Data Signals (DTM1, DFM1)

The default baud rate of the UARTs is auto-baud. Baud rates of between 600 bauds to 460 kbauds are possible. The wireless modem also supports 3GPP TS 27.010 multiplexing protocol, which starts when the appropriate command is sent.

LZT 123 1834

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