Serial Interfaces; Primary Uart (Uart1) - Motorola C24 CDMA 1X Hardware Interface Manual

Applicant: Motorola, INC

2.6 Serial Interfaces

The module includes 3 completely independent serial communications interfaces, which may be used by
the application for several purposes.
TABLE 5 – Serial Interfaces signals
Pin (s) Signal Name
9 RTS_N
11 RXD_N
13 DSR_N
15 CTS_N
17 DCD_N
19 DTR_N
21 TXD_N
23 RI_N
29 RXD2
31 TXD2
33 RTS2
35 CTS2
10 USB_VBUS
12 USB_DP
14 USB_DN
2.6.1

Primary UART (UART1)

The module's primary UART is a standard 8-signal bus. The primary UART is used for all the
communications with the module – AT commands interface, Data Calls 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.
The module 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
the following figure.
Description
Primary UART "Ready -To - Send" signal
Primary UART "Receive Data" signal
Primary UART "Data - Set - Ready" signal
Primary UART "Clear -To - Send" signal
Primary UART "Carrier Detect" signal
Primary UART "Data - Terminal - Ready" signal
Primary UART "Transmit Data" signal
Primary UART "Ring Indicator" signal
Secondary UART "Receive Data" signal
Secondary UART "Transmit Data" signal
Secondary UART "Ready -To - Send" signal
Secondary UART "Clear -To - Send" signal
USB bus power
USB bus differential serial data (positive)
USB bus differential serial data (negetive)
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C24 Hardware Interface Manual
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