Technical information

Serial Interfaces
22 G24-L Module Hardware Description November 15, 2008
Serial Interfaces
G24-L includes two completely independent serial communications interfaces, which may be
used by the application for several purposes.
UART
The G24-L UART is a standard 8-signal bus. The UART is used for all the communications with
G24-L - AT commands interface, GPRS data and CSD data, programming and software upgrades.
The UART signals are active low CMOS level signals. For standard RS232 communications with
a PC, an external transceiver is required.
G24-L is defined as a DCE device, and the user application is defined as the DTE device. These
definitions apply for the UART signals naming conventions, and the direction of data flow, as
described in Figure 2-11.
Figure 2-11: UART Interface Signals
The G24-L primary UART supports baud rates 300, 600, 1200, 2400, 4800, 9600, 19200, 38400,
57600 and 115200 bps.
Auto baud rate detection is supported for baud rates up to 115200 bps.
All flow control handshakes are supported: hardware, software, or none.
Parity bit and Stop bit definitions are also supported.
The UART default port configuration is 8 data bits, 1 stop bit and no parity, with hardware flow
control and auto baud rate detect enabled.
Important: The G24-L UART will not send data over the serial interface in case the DTR_N
and/or RTS_N input signals are disabled (set high). Therefore, regardless of the
handshake method, it is still required to enable these signals for proper operation, by
asserting them low.