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


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...  ");
    pc.printf("OK. Reset in 10 sec...\r\n");
    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


RevisionDateWhoCommit message
78:a03a5dade5b5 22 months ago WiredHome Renamed the WiflyInterface header and class name to EthernetInterface to be more readily swapped with the wired version. The TimeInterface then works directly. default tip
77:41f9c7987e0a 2018-04-11 WiredHome Documentation change (only).
76:d94cd478c7fc 2018-03-30 WiredHome Corrected defect where getting the MAC Address would clear the IP address.
75:4f8817f67f67 2018-03-30 WiredHome Disable excess debug
74:d20120171e35 2016-01-16 WiredHome UDP was trusting the endpoint to be configured - and persist in the definition of the host ip and port. Some code called APIs that reset that config, causing a failure. Current solution as implemented is to force the endpoint config each time.
73:59d0bbc4f905 2015-12-19 WiredHome Updated to align with EthernetInterface - added setName and get_connection_speed.; Updated the SWUpdate for the Wifly module, then tested to ensure it is working.
72:9499f5c1e00b 2015-12-19 WiredHome Improve API compatibility with EthernetInterface, even when that means some APIs return a failure-code, since WiflyInterface cannot do all that EthernetInterface can.
71:59936f711b80 2014-09-25 WiredHome Changes to more closely match the EthernetInterface APIs for improve interchangeability.; Increased the timeout in the FlushIn call after sending a command - this helps it clean up the response from a slow command.
70:83e420b0d3e1 2015-12-14 WiredHome Minor refactoring to eliminate wasted operations, and adapt to firmware v4.75
69:a4064f7e3529 2014-05-02 WiredHome Revised the ssid and passcode to be simple char arrays, simplifying the storage and management, but also meeting the required size.
68:d9a3920cc407 2014-04-27 WiredHome Updated documentation only to list the changes from a version of the mbed official library.
67:557ea7ad15c1 2014-04-19 WiredHome Revise the Wifly interface so that recovery from a lost connection is possible. See the "in_connected()" method for an example.
66:e52bd50e6d9f 2014-04-18 WiredHome remove a debug printf.
65:427518ba7b01 2014-04-18 WiredHome protect getIPAddress( ) from possible buffer overrun.
64:6202428f37ec 2014-04-18 WiredHome Updated the is_connected method to query the Wifly module. Actually returning "is associated" instead of "is connected".
63:fee0b25f1bf5 2014-04-18 WiredHome Corrected a long standing API defect. WiflyInterface::connect() should returns 0 on success, but was simply returning the return value of Wifly::join() which is a boolean true on success. So, this update correctly reversed the logic.
62:f1484c792c0e 2014-04-18 WiredHome SetSecurity() api needs to first reset the state object.
61:288691545d03 2014-03-09 WiredHome Turn off debug as the default.
60:03f1a99663e2 2014-03-08 WiredHome Corrected build failure when debug was enabled - it was still referencing the removed c++ string.
59:8e15d2ca7bd5 2014-03-06 WiredHome Revised the send() method for improved reliability.
58:f49aab8072ec 2014-03-01 WiredHome Update to support long SSIDs.; Add Wifly module software update API.; Increase time-out to 2500 ms to accommodate Wifly module behavior.; Update documentation.; Clean up dead code.; Revise the debug interface.
57:5259cf47106a 2014-01-04 WiredHome Documentation improvement.
56:eba4aabaad3e 2014-01-03 WiredHome Minor comment change related to INCREASE_SECURITY SW version required.; Added a small guard on the Wifly module logonText extraction - have not seen a need for this however it is good safeguarding.
55:0729959263b7 2014-01-03 WiredHome Updated documentation.; Remove unnecessary delay.; Minor code refactoring to improve maintenance.
54:f13529746357 2013-12-30 WiredHome Add small guard on one call to the cmdMode method.
53:3dd2e7f9edc0 2013-12-30 WiredHome Added a small guard on cmdMode in sendCommand.
52:ffc0b655a23c 2013-12-30 WiredHome Cleanup for compiler warning reduction.
51:a4831b1cb9a4 2013-11-28 WiredHome Documentation updates - put all files into a more similar format for the doxygen tags.; Reduce some of the verbose debugging information.; Small amount of code size reduction (reduced some redundancy)
50:cc173c24a316 2013-10-12 WiredHome Diagnostic changes only while trying to optimize performance.
49:81d6f0e1af23 2013-10-12 WiredHome Picked up a replacement MODSERIAL library that captures stdout to make debugging much easier.
48:b9e1152f39e3 2013-10-11 WiredHome Small change to the debug print to better line up with other files.
47:97303e1970c1 2013-10-10 WiredHome Fixed a defect in FixPhrase that was freeing memory that wasn't allocated.
46:4722f7d72aab 2013-10-10 WiredHome Security enhancements
45:21b7bbaad62b 2013-10-10 WiredHome Diagnostic improvements
44:dc8ef27bd311 2013-10-10 WiredHome Small documentation update
43:df984bf61580 2013-10-10 WiredHome Dead code removal
42:2a6fa071aecc 2013-10-10 WiredHome Enhanced debugging, but fails in SendResponse(...)
41:698be43f9233 2013-10-10 WiredHome Starting to add file upload capability.
40:07684f1d5f84 2013-10-09 WiredHome Documentation change only.
39:29e72dada2f5 2013-10-09 WiredHome Documentation changes only
38:30e142b93ce4 2013-10-09 WiredHome Minor documentation changes
37:84084567c4b9 2013-09-11 WiredHome Remove dead code in the accept method.
36:8d868fea6fe6 2013-09-10 WiredHome Minor modification to the accept() check for *OPEN*, as well as to the wifly send() method to check for the ACK string. This prevents it from potentially getting out of sync.
35:2dc12224cbd6 2013-09-06 WiredHome Modified a version extraction to handle both v2.36 and v4.00 (it was looking for a case sensitive match of wifly before it parsed Ver X.YY).; WiFly Ver 2.36, 09-27-2012 on RN-171; wifly-EZX Ver 4.00.1, Apr 19 2013 11:47:16 on RN-171
34:52e4eec8b790 2013-09-05 WiredHome Major change is in how to checks for expected response. Prior code used the C++ string method of concatenation, which could continue to allocate memory to exhaustion, even if it was only interested in a few character response.
33:25958bf80481 2013-09-01 WiredHome Revise the non-blocking - may override the desired timeout to a minimum of 10 msec because some parts of the socket are not well behaved with zero.
32:4543e91ab4bf 2013-09-01 WiredHome Implement the non-blocking option. The API was there to set it, but it was otherwise unused.
31:e4422f192d25 2013-08-12 WiredHome Added other security options back in.
30:f500260463b7 2013-08-05 WiredHome Add extra access point security methods supported by the Wifly module
29:49876a8c445b 2013-08-04 WiredHome Changes focused on connection reliability. A number of small changes to debug macros, while discovering that something kicks wifly out of command mode. So, the cmdMode() API forces a check. This seems to be a huge improvement.
28:b7c1182aed28 2013-07-27 WiredHome Add a delay on close. While delays are to be avoided, if there is data in the Wifly module still being sent, it appears that closing too soon can interrupt that transmission. Have not identified any synchronous way to determine the transmit is done.
27:8509ec4a0a0a 2013-07-22 WiredHome Change the flush size to 1420 and minor documentation tweaks nearby.
26:78a1a09afdc9 2013-07-22 WiredHome Modify the reboot method so it gets back in sync more easily.
25:a740eb74a86a 2013-07-22 WiredHome Improve security, and small formatting changes for more consistency.
24:5012a535b1d5 2013-07-21 WiredHome Refactored the ssid and passphrase handler to eliminate redundant code.
23:6e77c65ced00 2013-07-21 WiredHome Minor refactor on send() to share the timeout for both purposes.; Minor refactor on sendCommand to retry on failure.
22:62267088e95a 2013-07-21 WiredHome Improved the DEBUG behavior - printouts, extra \r\n, etc.
21:97294686b4a1 2013-07-21 WiredHome Add baud rate setting
20:906b0f951bc3 2013-07-21 WiredHome Add baud rate setting
19:b0c2488222a3 2013-07-21 WiredHome Efficiency - send() had 3 timers, a passed in timer which worked only when no ACK was expected, and two hard-coded timers for when the caller wanted the return ACK. Eliminated the hard-coded timers.