Serial Interfaces; Primary Uart (Uart1) - Motorola G24 Developer's Manual

Serial Interfaces

Serial Interfaces
G24 includes three completely independent serial communications interfaces, which may be used
by the application for several purposes.

Primary UART (UART1)

The G24 primary UART is a standard 8-signal bus. The primary UART is used for all the
communications with G24 - 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 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 2-12: UART1 Interface Signals
The G24 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 460 kbps.
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:
24
Figure 2-12.
The G24 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.
Module Hardware Description January 1, 2006