MODIFIED from mbed official WiflyInterface (interface for Roving Networks Wifly modules). Numerous performance and reliability improvements (see the detailed documentation). Also, tracking changes in mbed official version to retain functional parity.

Dependents:   Smart-WiFly-WebServer PUB_WiflyInterface_Demo

Fork of WiflyInterface by mbed official

Resources

Derivative from mbed Official

  • Documentation update, improved consistency, documented parameters that were inadvertently omitted.
  • Avoid c++ string handling, which causes dynamic allocation and free, side effect, fewer CPU cycles spent for same purpose.
  • Fixed socket APIs to support non-blocking mode.
  • Increase communication baud-rate to Wifly module
  • sendCommand - added retries for improved robustness.
  • setConnectionState - method to force the connection state (used by TCPSocketServer)
  • gethostbyname - added a length parameter to the size of the buffer being written
  • flushIn - a private method to flush the input buffer
  • Changed the timeout from 500 to 2500 msec for commands - measured some at 700 to 850 msec.
  • Performance improvements - reduced some unnecessary delays.
  • Added additional security options for the wi-fi connection (that are supported by the WiFly module).
  • Added setSecurity API which permits revising the security when connecting to, or selecting from, one of several access points.
  • Improved DEBUG interface (slightly more consistent printout).
  • gathers information from the Wifly module on reboot (SW version info), which permits customizing behavior based on Wifly capabilities (like the improved security).
  • Avoid potential for recursive crash (if exit fails, it calls sendcommand, which calls exit...)
  • Update to support permissible SSID and PassCode lengths.

Robustness testing

I've had some mixed behavior with the Wifly module, some of which seems to be traceable to the module itself, and some in my derivative code. The result, after running for minutes, hours, sometimes days, it hangs and I have to reset the module.

To test, I created a fairly simple test program -

  • check for Watchdog induced reset and count it.
  • initialize the Watchdog for 60 sec timeout.
  • Init the Wifly interface and connect to my network.
  • Wait 10 seconds and force mbed_reset().

If the Watchdog induces the restart, then it is pretty clear that either:

  • The communications hung with the Wifly module causing the failure.
  • The Wifly module decided to go unresponsive.

If it gets to the end, it typically takes about 4 to 6 seconds for the boot and connect, then the 10 second delay.

But I can't really pin down the root cause easily. My strongest theory is that the Wifly module has rebooted, and since I don't store the high baud rate I configure it for, it resets back to 9600.

Also, one of the objectives for my revised send( ) is to avoid the c++ string, as that can fragment memory, and it wasn't very well bounded in behavior.

Latest tests:

Warm BootsWatchdog EventsNotes
100's30An early version of my derivative WiflyInterface, including my derivative of "send( )" API. Let's call this version 0.1.
26684My derivative WiflyInterface, but with the mbed official "send( )" API. Much improved. This was over the course of about 12 hours.
24003Most recent derivative - incremental change to "send( )", but this relative number does not rule out the Wifly module itself.

I think with these numbers, +/- 1 means that the changes have had no measurable effect. Which is good, since this incremental change eliminates the c++ string handling.

Test Software

This is pieces of a test program, clipped and copied to here. What I have compiled and run for hours and hours is almost exactly what you see. This uses this simple Watchdog library.

#include "mbed.h"
#include "WiflyInterface.h"
#include "Watchdog.h"

Serial pc(USBTX, USBRX);

Watchdog wd;
extern "C" void mbed_reset();

// Pinout for SmartBoard
WiflyInterface wifly(p9, p10, p30, p29, "ssid", "pass", WPA);

int main() {
    pc.baud(460800);                         // I like a snappy terminal
    
    wd.Configure(60.0);                     // Set time limit for the test to 1 minute
    LPC_RTC->GPREG0++;                      // Count boots here
    if (wd.WatchdogCausedReset()) {
        LPC_RTC->GPREG1++;                  // Count Watchdog events here
        pc.printf("\r\n\r\nWatchdog event.\r\n");
    }
    pc.printf("\r\nWifly Test: %d boots, %d watchdogs. %s %s\r\n", LPC_RTC->GPREG0, LPC_RTC->GPREG1, __DATE__, __TIME__);
    
    wifly.init(); // use DHCP
    pc.printf("Connect...  ");
    while (!wifly.connect());               // join the network
    pc.printf("Address is %s.  ", wifly.getIPAddress());
    pc.printf("Disconnect...  ");
    wifly.disconnect();
    pc.printf("OK. Reset in 10 sec...\r\n");
    wait(10);
    if (pc.readable()) {
        if (pc.getc() == 'r') {             // secret 'r'eset of the counters
            LPC_RTC->GPREG0 = 0;
            LPC_RTC->GPREG1 = 0;
            pc.printf("counters reset\r\n");
        }
    }
    mbed_reset();                           // reset here indicates successful communication
}

Files at this revision

API Documentation at this revision

Comitter:
WiredHome
Date:
Sun Jul 21 16:15:00 2013 +0000
Parent:
14:473d73cb48ee
Child:
16:55b5c1f9b8ed
Commit message:
Updated the documentation so the methods appear and documented parameters that existed, but were not previously documented.

Changed in this revision

Wifly/Wifly.h Show annotated file Show diff for this revision Revisions of this file
--- a/Wifly/Wifly.h	Sun Jul 21 15:55:28 2013 +0000
+++ b/Wifly/Wifly.h	Sun Jul 21 16:15:00 2013 +0000
@@ -43,11 +43,15 @@
     TCP = (1 << 1)
 };
 
+/** the Wifly object
+*
+* This object controls the Wifly module.
+*/
 class Wifly
 {
 
 public:
-    /*
+    /**
     * Constructor
     *
     * @param tx mbed pin to use for tx line of Serial interface
@@ -60,21 +64,21 @@
     */
     Wifly(  PinName tx, PinName rx, PinName reset, PinName tcp_status, const char * ssid, const char * phrase, Security sec);
 
-    /*
+    /**
     * Connect the wifi module to the ssid contained in the constructor.
     *
     * @return true if connected, false otherwise
     */
     bool join();
 
-    /*
+    /**
     * Disconnect the wifly module from the access point
     *
     * @ returns true if successful
     */
     bool disconnect();
 
-    /*
+    /**
     * Open a tcp connection with the specified host on the specified port
     *
     * @param host host (can be either an ip address or a name. If a name is provided, a dns request will be established)
@@ -84,7 +88,7 @@
     bool connect(const char * host, int port);
 
 
-    /*
+    /**
     * Set the protocol (UDP or TCP)
     *
     * @param p protocol
@@ -92,50 +96,50 @@
     */
     bool setProtocol(Protocol p);
 
-    /*
+    /**
     * Reset the wifi module
     */
     void reset();
     
-    /*
+    /**
     * Reboot the wifi module
     */
     bool reboot();
 
-    /*
+    /**
     * Check if characters are available
     *
     * @return number of available characters
     */
     int readable();
 
-    /*
+    /**
     * Check if characters are available
     *
     * @return number of available characters
     */
     int writeable();
 
-    /*
+    /**
     * Check if a tcp link is active
     *
     * @returns true if successful
     */
     bool is_connected();
 
-    /*
+    /**
     * Read a character
     *
     * @return the character read
     */
     char getc();
 
-    /*
+    /**
     * Flush the buffer
     */
     void flush();
 
-    /*
+    /**
     * Write a character
     *
     * @param the character which will be written
@@ -143,28 +147,28 @@
     int putc(char c);
 
 
-    /*
+    /**
     * To enter in command mode (we can configure the module)
     *
     * @return true if successful, false otherwise
     */
     bool cmdMode();
 
-    /*
+    /**
     * To exit the command mode
     *
     * @return true if successful, false otherwise
     */
     bool exit();
 
-    /*
+    /**
     * Close a tcp connection
     *
     * @ returns true if successful
     */
     bool close();
 
-    /*
+    /**
     * Send a string to the wifi module by serial port. This function desactivates the user interrupt handler when a character is received to analyze the response from the wifi module.
     * Useful to send a command to the module and wait a response.
     *
@@ -173,23 +177,25 @@
     * @param len string length
     * @param ACK string which must be acknowledge by the wifi module. If ACK == NULL, no string has to be acknoledged. (default: "NO")
     * @param res this field will contain the response from the wifi module, result of a command sent. This field is available only if ACK = "NO" AND res != NULL (default: NULL)
+    * @param timeout is the time in msec to wait for the acknowledge
     *
     * @return true if ACK has been found in the response from the wifi module. False otherwise or if there is no response in 5s.
     */
     int send(const char * str, int len, const char * ACK = NULL, char * res = NULL, int timeout = DEFAULT_WAIT_RESP_TIMEOUT);
 
-    /*
+    /**
     * Send a command to the wify module. Check if the module is in command mode. If not enter in command mode
     *
     * @param str string to be sent
     * @param ACK string which must be acknowledge by the wifi module. If ACK == NULL, no string has to be acknoledged. (default: "NO")
     * @param res this field will contain the response from the wifi module, result of a command sent. This field is available only if ACK = "NO" AND res != NULL (default: NULL)
+    * @param timeout is the time in msec to wait for the acknowledge
     *
     * @returns true if successful
     */
     bool sendCommand(const char * cmd, const char * ack = NULL, char * res = NULL, int timeout = DEFAULT_WAIT_RESP_TIMEOUT);
     
-    /*
+    /**
     * Return true if the module is using dhcp
     *
     * @returns true if the module is using dhcp
@@ -198,6 +204,14 @@
         return state.dhcp;
     }
 
+    /**
+    * gets the host ip address
+    *
+    * @param host is a pointer to the host string to look up
+    * @param ip contains the host IP in a string after the lookup.
+    * @param sizeof_ip is the size of the buffer pointed to by ip
+    * @returns true if successful
+    */
     bool gethostbyname(const char * host, char * ip);
 
     static Wifly * getInstance() {