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
}
Committer:
samux
Date:
Fri Aug 24 13:48:36 2012 +0000
Revision:
1:fb4494783863
first commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
samux 1:fb4494783863 1 /* Copyright (C) 2012 mbed.org, MIT License
samux 1:fb4494783863 2 *
samux 1:fb4494783863 3 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
samux 1:fb4494783863 4 * and associated documentation files (the "Software"), to deal in the Software without restriction,
samux 1:fb4494783863 5 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
samux 1:fb4494783863 6 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
samux 1:fb4494783863 7 * furnished to do so, subject to the following conditions:
samux 1:fb4494783863 8 *
samux 1:fb4494783863 9 * The above copyright notice and this permission notice shall be included in all copies or
samux 1:fb4494783863 10 * substantial portions of the Software.
samux 1:fb4494783863 11 *
samux 1:fb4494783863 12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
samux 1:fb4494783863 13 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
samux 1:fb4494783863 14 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
samux 1:fb4494783863 15 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
samux 1:fb4494783863 16 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
samux 1:fb4494783863 17 */
samux 1:fb4494783863 18
samux 1:fb4494783863 19 #ifndef CIRCBUFFER_H_
samux 1:fb4494783863 20 #define CIRCBUFFER_H_
samux 1:fb4494783863 21
samux 1:fb4494783863 22 template <class T>
samux 1:fb4494783863 23 class CircBuffer {
samux 1:fb4494783863 24 public:
samux 1:fb4494783863 25 CircBuffer(int length) {
samux 1:fb4494783863 26 write = 0;
samux 1:fb4494783863 27 read = 0;
samux 1:fb4494783863 28 size = length + 1;
samux 1:fb4494783863 29 buf = (T *)malloc(size * sizeof(T));
samux 1:fb4494783863 30 };
samux 1:fb4494783863 31
samux 1:fb4494783863 32 bool isFull() {
samux 1:fb4494783863 33 return (((write + 1) % size) == read);
samux 1:fb4494783863 34 };
samux 1:fb4494783863 35
samux 1:fb4494783863 36 bool isEmpty() {
samux 1:fb4494783863 37 return (read == write);
samux 1:fb4494783863 38 };
samux 1:fb4494783863 39
samux 1:fb4494783863 40 void queue(T k) {
samux 1:fb4494783863 41 if (isFull()) {
samux 1:fb4494783863 42 read++;
samux 1:fb4494783863 43 read %= size;
samux 1:fb4494783863 44 }
samux 1:fb4494783863 45 buf[write++] = k;
samux 1:fb4494783863 46 write %= size;
samux 1:fb4494783863 47 }
samux 1:fb4494783863 48
samux 1:fb4494783863 49 void flush() {
samux 1:fb4494783863 50 read = 0;
samux 1:fb4494783863 51 write = 0;
samux 1:fb4494783863 52 }
samux 1:fb4494783863 53
samux 1:fb4494783863 54
samux 1:fb4494783863 55 uint32_t available() {
samux 1:fb4494783863 56 return (write >= read) ? write - read : size - read + write;
samux 1:fb4494783863 57 };
samux 1:fb4494783863 58
samux 1:fb4494783863 59 bool dequeue(T * c) {
samux 1:fb4494783863 60 bool empty = isEmpty();
samux 1:fb4494783863 61 if (!empty) {
samux 1:fb4494783863 62 *c = buf[read++];
samux 1:fb4494783863 63 read %= size;
samux 1:fb4494783863 64 }
samux 1:fb4494783863 65 return(!empty);
samux 1:fb4494783863 66 };
samux 1:fb4494783863 67
samux 1:fb4494783863 68 private:
samux 1:fb4494783863 69 volatile uint32_t write;
samux 1:fb4494783863 70 volatile uint32_t read;
samux 1:fb4494783863 71 uint32_t size;
samux 1:fb4494783863 72 T * buf;
samux 1:fb4494783863 73 };
samux 1:fb4494783863 74
samux 1:fb4494783863 75 #endif