serial_wifi

Table of Contents

Overview

Serial WiFi is a capability designed to provide easy, self-contained terminal access behavior, over UART interface. It also provides a ‘driver-less’ solution which allows the use of AT Commands to operates the various range of networking capabilities which the CC3220/CC3120 device family provides. This application runs over the UART interface, behaves as a command line interpreter and allows secure, robust end-to-end communication. For details about the AT Commands and thier parameters please refer to the AT Commands and attributes: Commands and attributes

Usage

The connection should have the following connection settings:

    Baud-rate:    115200
    Data bits:         8
    Stop bits:         1
    Parity:         None
    Flow Control:   None

Once the application has complete it’s initialization and the network processor is up,
the application banner would be displayed, showing version details:

         ==============================================
            Serial WIFI Example Ver: 1.1.1
         ==============================================

         CHIP: 0x20000010
         MAC:  2.0.0.0
         PHY:  2.2.0.4
         NWP:  3.2.0.0
         ROM:  0
         HOST: 2.0.1.17
         MAC address: 08:00:28:5b:55:e0

         ==============================================

First, the device tries to connect to the stored AP by the AUTO connect policy. If the device doesn’t connect to an AP in 6secs, the application prompts the user to connect to a known AP using the Local control mode. special escape sequence prefix \\< is used to define AT Command in local control mode (mode in which we control the local Simplelink device). User can use AT WLAN connect command to connect to an AP:

\\<AT+WlanConnect = [SSID],[BSSID],[SecurityType],[SecurityKey],[SecurityExtUser],[SecurityExtAnonUser],[SecurityExtEapMethod]

Or use AT WLAN add profile to connect to an AP and create profile for auto connect next time:

\\<AT+WlanProfileAdd = [SSID],[BSSID],[SecurityType],[SecurityKey],[SecurityExtUser],[SecurityExtAnonUser],[SecurityExtEapMethod],[Priority]

For example:

\\<at+wlanconnect=TP-LINK_123456,,open,,,,
\\<at+wlanprofileadd=TP-LINK_123456,,open,,,,,6

After connection is established with the AP, the device search automatically for remote peer by mDNS. Once the remote peer was founded, the device try to connect it based on secure sockets (all certificate files should be flash by using the Uniflash tool for cc32xx)
Default Security method is SSLV3 and Cipher is RSA WITH RC4 128 SHA.

At this point, user can take control over the remote peer by AT commands or simply send data from Local UART to the remote UART. special escape sequence prefix \\> is used to define AT Command in remote control mode (mode in which we control the remote Simplelink device).

Application details

  1. Provides access to all the SimpleLink Host APIs through the AT commands instruction set
  2. Auto discovery of available peer using mDNS
  3. All communication is secure using the Secure Sockets
  4. Terminal mode for serial cable replacement
  5. Local/Remote Control modes, to issue commands to the locally/remotely connected Simplelink device.
  1. Terminal mode: In this case the interpreter mode behaves as pure point-to-point cable replacement. This is the most common and obvious use in which a serial cable formerly used to carry information is replaced by SimpleLink devices on both end of the line. As default all data that comes from the UART will be routed to the remote peer unless it is local or remote control data which has special escape sequence prefix
  2. Local control mode: In this mode it is possible to issue AT commands to the locally connected device. The AT commands library encompass a close set of options to control the SimpleLink device while guaranteeing sandbox restrictions. In order to issue local control command, add special escape sequence prefix (//<) to the AT command.
  3. Remote control mode: This allows issuing AT commands to the remotely connected device the same as the Local control commands. In order to issue remote control command, add special escape sequence prefix (//>) to the AT command.

Commands

Syntax:

    AT<command name>=<param1>, <param2>,  ,<paramX>

Command return status

Command return status could be one of the following cases:

Asynchronous event

The events may arrive at any time. They will always be built in the following format:

    <event name>: <event ID>,<value1>, ,<valueX>

Please install the latest CC32xx Service Pack in order to get the most optimization and lowest current consumption.

References

For full list of commands and attributes, please refer to Commands and attributes