Revision 21:97294686b4a1, committed 2013-07-21

Comitter:

WiredHome

Date:

Sun Jul 21 23:05:51 2013 +0000

Parent:

19:b0c2488222a3

Child:

22:62267088e95a

Commit message:

Add baud rate setting

Changed in this revision

--- a/Wifly/Wifly.cpp	Sun Jul 21 21:14:57 2013 +0000
+++ b/Wifly/Wifly.cpp	Sun Jul 21 23:05:51 2013 +0000
@@ -43,7 +43,7 @@
 Wifly * Wifly::inst;
 
 Wifly::Wifly(   PinName tx, PinName rx, PinName _reset, PinName tcp_status, const char * ssid, const char * phrase, Security sec):
-    wifi(tx, rx), reset_pin(_reset), tcp_status(tcp_status), buf_wifly(256)
+    wifi(tx, rx), reset_pin(_reset), tcp_status(tcp_status), baudrate(9600), buf_wifly(256)
 {
     memset(&state, 0, sizeof(state));
     state.sec = sec;
@@ -545,3 +545,55 @@
     DBG("Wifly::flushIn(%d) {%s}", timeout_ms, chatter);
 #endif
 }
+
+
+// The ARM uart and the Wifly uart have to be in sync or we get
+// no meaningful response, so then have to try the possibilities.
+//
+// First try is at the currently configured ARM uart baud, if
+// that fails then it shifts the ARM uart baud through the probable
+// speeds, trying to establish contact with the Wifly module.
+// Once contact is demonstrated (response to the 'ver' command),
+// then it sets the Wifly module and then the ARM uart.
+bool Wifly::baud(int _targetBaud)
+{
+    // in testing, 460800 and 921600 may change the Wifly module where you can't
+    // change it back w/o a reset. So, we won't even permit those speeds.
+    const int baudrates[] = {2400, 4800, 9600, 19200, 38400, 57600, 115200, 230400};    //, 460800, 921600};
+#define BRCOUNT (sizeof(baudrates)/sizeof(baudrates[0]))
+    char cmd[20];       // sized for "set u i 460800\r" [15+1], plus margin [4]
+    int tryIndex = 0;
+    bool res = false;
+    int userIndex;
+
+    sprintf(cmd, "set u i %d\r", _targetBaud);
+    // set u i # should cause it to exit command mode (manual 2.3.64),
+    // but testing indicates that it does not.
+    for (userIndex=0; userIndex < BRCOUNT; userIndex++) {
+        if (_targetBaud == baudrates[userIndex]) {
+            while (tryIndex <= BRCOUNT) {
+                DBG("baud(%d) try: %d", _targetBaud, tryIndex);
+                sendCommand(cmd); // shift Wifly to desired speed [it may not respond (see 2.3.64)]
+                // state.cmd_mode = false;  // see note above why this is disabled
+                wifi.baud(_targetBaud);     // shift the ARM uart to match
+                if (sendCommand("ver\r", "wifly", NULL, timeToRespond(4))) {  // use this to verify communications
+                    baudrate = _targetBaud;
+                    res = true;
+                    break;              // success
+                }
+                // keep trying baudrates between ARM and WiFly
+                if (tryIndex < BRCOUNT) {
+                    wifi.baud(baudrates[tryIndex]);
+                }
+                tryIndex++;
+            }
+            break;  // if they selected a legitimate baud, try no others
+        }
+    }
+    return res;
+}
+
+int Wifly::timeToRespond(int stringLen) 
+{
+    return 150 + (1 | 10000/baudrate) * stringLen;
+}

--- a/Wifly/Wifly.h	Sun Jul 21 21:14:57 2013 +0000
+++ b/Wifly/Wifly.h	Sun Jul 21 23:05:51 2013 +0000
@@ -214,6 +214,26 @@
     */
     bool gethostbyname(const char * host, char * ip);
 
+    /**
+    * Set the baud rate between the ARM and the WiFly.
+    *
+    * This will set the WiFly module baud rate first and then
+    * set the ARM interface to match it. If it cannot get the proper 
+    * acknowledge response, it will go on a hunt through the range 
+    * of standard baud rates.
+    *
+    * @note Baud rate must be one of 2400, 4800, 9600, 19200, 38400, 57600,
+    *       115200, 230400, 460800, or 921600. (See Wifly manual 2.3.64)
+    * @note Baud rate of 230400 has been seen to be marginal w/o flow control.
+    * @note Setting a baud rate to a 460800 or above may be unrecoverable
+    *       without resetting the Wifly module.
+    *
+    * @param baudrate is the desired baudrate.
+    * @returns true if it succeeded, which means that communications can continue, 
+    * @returns false if it failed to establish a communication link.
+    */
+    bool baud(int baudrate);
+
     static Wifly * getInstance() {
         return inst;
     };
@@ -222,6 +242,7 @@
     Serial wifi;
     DigitalOut reset_pin;
     DigitalIn tcp_status;
+    int baudrate;
     char phrase[30];
     char ssid[30];
     const char * ip;
@@ -246,6 +267,15 @@
 
     State state;
     char * getStringSecurity();
+    
+    /**
+    * Estimates the time needed for the Wifly module to respond
+    * to some of the simple commands.
+    *
+    * @param stringLength is the number of characters in the command
+    * @returns number of milliseconds.
+    */
+    int timeToRespond(int stringLen);
 };
 
 #endif
\ No newline at end of file