John Bailey / XBeeApi

API for communicating with XBee devices.

Dependencies:   CircularBuffer FixedLengthList

Dependents:   XBeeApiTest XBeeApiSimpleATCmdsExample XBeeApiBroadcastExample XBeeApiBroadcastExampleRTOS ... more

Overview

XBeeApi is intended to be a library for providing a high-level API interface to the XBee - for example getChannel() and setChannel(2) methods rather than needing to send( "ATCH" ) and send( "ATCH 2" ) - and then de-code the responses.

See the notebook page here for a description of how the API works & some details on the various classes.

Features:

  • Support for transmission & reception of data packets
  • Support for reading & changing settings
  • Support for "Remote AT" interface to access settings & I/O channels on remote XBees
  • XBeeApi should work if you're using mbed-rtos, though it is not currently threadsafe. Take a look at the XBeeApiBroadcastExampleRTOS example if you're including mbed-rtos.

Example Programs

There are also example programs available:

Transmit

Import programXBeeApiSimpleBroadcastExample

Simple example of how to use XBeeApi - set up the XBee, configure P2P networking then transmit a frame.

Last commit 06 Jul 2014 by John Bailey

Import programXBeeApiBroadcastExample

Example for XBeeAPI; a little more involved than XBeeApiSimpleBroadcastExample with report on failure to set up the XBee and on the transmit status of the message.

Last commit 05 Jul 2014 by John Bailey

Import programXBeeApiBroadcastExampleRTOS

Example of using the XBeeApi library to broadcast a message, based on XBeeApiBroadcastExample. This example shows how to use the library when using mbed-rtos. Before compiling you must open "XbeeApi\Config\XBeeApiCfg.hpp" and change the '#if 0' to '#if 1' on the line above the comment reading "Use RTOS features to make XBeeApi threadsafe"

Last commit 06 Jul 2014 by John Bailey

Settings/Status

Import programXBeeApiSimpleATCmdsExample

Simple example of using XBeeApi to send AT-style commands to the XBee

Last commit 31 Mar 2014 by John Bailey

Import programXBeeApiRemoteATCmdsExample

Example of using the XBeeApi library to send AT commands to remote XBee devices in order to read/write settings

Last commit 13 Jul 2014 by John Bailey

Receive

Import programXBeeApiSimpleReceiveExample

Simple example of using XBeeApi to receive data packets via wireless

Last commit 08 Jul 2014 by John Bailey

Import programXBeeApiReceiveCallbackExample

Example of using the XBeeApi library to receive a message via a callback method

Last commit 08 Jul 2014 by John Bailey

Import programXBeeApiReceiveCallbackExampleRTOS

Example of using the XBeeApi library to receive a message via a callback method. This example shows how to use the library when using mbed-rtos. See the comment at the top of main.cpp

Last commit 08 Jul 2014 by John Bailey

Remote I/O

Import programXBeeApiRemoteIOExample

Example of using the XBeeApi library to read inputs on a remote XBee

Last commit 28 Jul 2014 by John Bailey

If you have 2 mbed connected XBees available then you can use XBeeApiSimpleReceiveExample and XBeeApiSimpleBroadcastExample as a pair.

Note that this is still a work in progress! XBeeApiTodoList tracks some of the functionality still to be added.

Diff: Base/XBeeDevice.cpp

Revision:
48:48397bedf95d
Parent:
43:975a28e01dac
Child:
49:37bba77ee73f
--- a/Base/XBeeDevice.cpp	Sun Jul 06 22:10:28 2014 +0000
+++ b/Base/XBeeDevice.cpp	Mon Jul 07 19:03:09 2014 +0000
@@ -79,6 +79,9 @@
     m_inAtCmdMode = false;
     m_rxMsgLastWasEsc = false;
     m_escape = true;
+    m_ignoreBadCsum = false;
+    m_badCsumCount = 0U;
+    m_serialBytesDiscarded = 0U;
 }
 
 XBeeDevice::XBeeDevice( PinName p_tx, PinName p_rx, PinName p_rts, PinName p_cts ):  m_serialNeedsDelete( true )
@@ -193,6 +196,7 @@
           ( m_rxBuff[0] != XBEE_SB_FRAME_DELIMITER ))
     {
         m_rxBuff.chomp( 1 );
+        m_serialBytesDiscarded++;
     }
     
     do {
@@ -211,18 +215,31 @@
             /* Check that we've received the entire frame */
             if( len >= cmdLen )
             {
-                /* TODO: Verify checksum */
+                bool doProcess = true;
+
+                /* Checksum verification, performed only if it's configured */
+                if( !m_ignoreBadCsum )
+                {
+                    if( !verifyFrameChecksum( cmdBuff, cmdLen ))
+                    {
+                        doProcess = false;
+                        m_badCsumCount++;
+                    }
+                }
                 
-                /* Iterate all of the decoders */
-                for( FixedLengthList<XBeeApiFrameDecoder*, XBEEAPI_CONFIG_DECODER_LIST_SIZE>::iterator it = m_decoders.begin() ;
-                     it != m_decoders.end();
-                     ++it ) {
+                if( doProcess )
+                {
+                    /* Iterate all of the decoders */
+                    for( FixedLengthList<XBeeApiFrameDecoder*, XBEEAPI_CONFIG_DECODER_LIST_SIZE>::iterator it = m_decoders.begin() ;
+                         it != m_decoders.end();
+                         ++it ) {
+        
+                        bool processed = (*it)->decodeCallback( cmdBuff, cmdLen );
     
-                    bool processed = (*it)->decodeCallback( cmdBuff, cmdLen );
-
-                    if( processed )
-                    {
-                        break;
+                        if( processed )
+                        {
+                            break;
+                        }
                     }
                 }            
                 /* Remove the data from the receive buffer - either it was decoded (all well and good)
@@ -431,6 +448,45 @@
     return ret_val;
 }
 
+void XBeeDevice::setIgnoreBadChecksum( const bool p_shouldIgnore )
+{
+    m_ignoreBadCsum = p_shouldIgnore;
+}
+     
+uint16_t XBeeDevice::getBadChecksumCount( void ) const
+{
+    return m_badCsumCount;
+}
+
+uint16_t XBeeDevice::getSerialBytesDiscardedCount( void ) const
+{
+    return m_serialBytesDiscarded;
+}
+
+bool XBeeDevice::verifyFrameChecksum( const uint8_t* const p_data, size_t p_len )
+{
+    /* TODO: Could try and be "smarter" and build the checksum as the frame is RX'd */
+
+    /* Don't include bytes that aren't checksummed */
+    size_t ctr = p_len - XBEE_API_FRAME_OVERHEAD;
+    /* Skip over the start delimiter and length (not included in checksum) */
+    const uint8_t* dat = p_data + XBEE_API_FRAME_OVERHEAD_START;
+    
+    uint8_t sum = 0;
+
+    do
+    {
+        sum += *dat;
+        dat++;
+        ctr--;
+    } while( ctr > 0 );
+
+    sum = 0xFFU - sum;
+    
+    return( sum == (*dat));
+}
+
+
 #if defined XBEEAPI_CONFIG_USING_RTOS && defined XBEEAPI_CONFIG_RTOS_USE_DISPATCHER
 bool XBeeDevice::setupDispatchTask( void )
 {