Chapter 2: Hardware Interface Description
May 31, 2008 Module Hardware Description 21
Serial Interfaces
W24 includes three completely independent serial communications interfaces, which may be
used by the application for several purposes (see Figure 2-10).
Figure 2-10: Serial Interfaces Block Diagram

Primary UART (UART1)

The W24 primary UART is a standard 8-signal bus. The primary UART is used for all the
communications with W24 - AT+i commands interface, Wi-Fi data, and G24- AT command
Interface (stacked configuration), 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.
W24 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:UART1 Interface Signals