Sony Ericsson GR47/GR48 Manuale Utente

5. SYSTEM CONNECTOR INTERFACE

37

LZT 123 7589 R1A

Digital 2.75 V CMOS input/output electrical characteristics apply.

The standard character format consists of 1 start bit, 8 bit data, no parity 
and 1 stop bit. In all, there are 10 bits per character.

UART1 signals conform to a 9-pin RS232 (V.24) serial port.

UART1 signal levels do not match standard RS232 (V.28) levels. The 
relationship between the levels is shown in the table below. 

Conversion between the radio device CMOS levels and RS232 levels can be 
achieved using a standard interface IC, such as the Maxim Integrated 
Products MAX3237.

The default baud rate is 9.6 kbits/s, however higher bit rates of up to 
460 kbits/s are supported, set by an AT command. UART1 starts at a rate 
of 9.6 kbits/s in standard AT command mode. The radio device also 
supports GSM 07.10 multiplexing protocol and starts when the 
appropriate command is sent.

RD is an output signal that the radio device uses to send data via UART1 
to the application.

TD is an input signal, used by the application to send data via UART1 to 
the radio device.

< –  3 V

1

OFF

> 1.93 V

> + 3 V

0

ON

< 0.80 V

Application load resistance

<

 

100 k

Ω

Application  load  capacitance

< 100 pF

Application driving impedance

< 100 

Ω

Input capacitance

1nF

Input resistance

100 k

Ω 

to 2.75 V