Sony Ericsson GR47/GR48 Manuale Utente

5. SYSTEM CONNECTOR INTERFACE

38

LZT 123 7589 R1A

UART1 control signals are active low and need a standard interface IC, 
such as the MAX3237, to generate standard RS232 levels.

UART1 converted signals, together with DGND, RD and TD form a 
9-pin RS232 data port.

RTS and CTS are capable of transmitting at 1/10

th

 of the data transmission 

speed for data rates up to 460 kbit/s (byte-oriented flow control 
mechanism).

When hardware flow control is not used in communications between the 
application and the radio device, RTS and CTS must be connected to each 
other at the radio device.

The table below shows the switching times.

Used to condition the DCE for data transmission. The default level is high 
by internal pull up.

The application must pull RTS low to enable data transmission from the 
radio device. Similarly, the radio device asserts CTS low, indicating it is 
ready to receive data transmission from the host.

CTS is asserted by the DCE to indicate that the host (DTE) may transmit 
data. When CTS is high, the host (DTE) is not permitted to transmit data.

The table below shows the load characteristics for this signal. 

Time from Low to High level

< 

2 µs

Time from High to Low level

< 

2 µs

Application driving impedance

< 100 

Ω

Input capacitance

< 2 nF

Input resistance (pull-up)

100 k

Ω

 to DGND

Application load capacitance

< 500 pF

Application load resistance

≥

 

1 M

Ω