myapp_ex03b.c

This network protcol stack,it is very strong and powerful!

/******************************************************************************
*   MyApp_Ex01.c  - Initialization and main loop. 
*   MyApp_Ex02.c  - Energy Detection Scan
*   MyApp_Ex03a.c - A PAN Coordinator is started
* = MyApp_Ex03b.c - Device locates coordinator using Active Scan = This file ==
*   MyApp_Ex04a.c - Coordinator responds to an Associate request
*   MyApp_Ex04b.c - Device Associates to the PAN coordinator
*   MyApp_Ex05a.c - Coordinator receives data from device
*   MyApp_Ex05b.c - Device sends direct data to the coordinator
*   MyApp_Ex06a.c - Coordinator sends indirect data to device
*   MyApp_Ex06b.c - Device polls for data from the coordinator
*   MyApp_Ex07a.c - Coordinator starts a beaconed network
*   MyApp_Ex07b.c - Device receives data using automatic polling
*   MyApp_Ex08a.c - Coordinator uses security
*   MyApp_Ex08b.c - Device uses security
*
* This demo application builds upon MyApp_Ex01.c. The primary purpose of this
* application is to demonstrate how to use the Active Scan feature of the MAC
* in order to locate a coordinator that we will associate to later.
* 
* The steps required for locating a coordinator are:
* 1) Build and send an MLME-Scan Request message to the MAC.
* 2) Wait for the MLME-Scan Confirm message from the MAC.
*
* Step 1 is performed by the 'stateScanActiveStart' state, and step 2 is 
* performed by the 'stateScanActiveWaitConfirm' state.
*
******************************************************************************/

#include "802_15_4.h" /* Include everything related to the 802.15.4 interface*/
#include "Uart.h"     /* Defines the interface of the demo UART. */
#include "ToolBox.h"

/* Defines the channels to scan. Each bit represents one channel. Use
   0x07FFF800 to scan all 16 802.15.4 channels in the 2.4GHz band. */
#define SCAN_CHANNELS 0x07FFF800

/* Forward declarations of helper functions */
uint8_t App_StartScan(uint8_t scanType);
uint8_t App_HandleScanActiveConfirm(nwkMessage_t *pMsg);
uint8_t App_WaitMsg(nwkMessage_t *pMsg, uint8_t msgType);

/* All states in the applications state machine */
enum {
  stateInit,
  stateScanActiveStart,
  stateScanActiveWaitConfirm,
  stateListen,
  stateTerminate
};

/* Error codes */
enum {
  errorNoError,
  errorWrongConfirm,
  errorNotSuccessful,
  errorNoMessage,
  errorAllocFailed,
  errorInvalidParameter,
  errorNoScanResults
};


/* The current state of the applications state machine */
uint8_t state;

/* Information about the PAN we are part of */
panDescriptor_t coordInfo;

/* Application input queues */
anchor_t mMlmeNwkInputQueue;


/* Application Main Loop */
void main(void)
{ 
  /* Pointer for storing the messages from MLME, MCPS, and ASP. */
  void *pMsgIn;
  /* Stores the status code returned by some functions. */
  uint8_t rc;
  /* return value of Mlme_Main() - not used yet */
  uint8_t macStatus;
  
  /* Initialize variables */
  state = stateInit;

  /* Prepare input queues.*/
  MSG_InitQueue(&mMlmeNwkInputQueue);

  /* Execute the application state machine */    
  while(state < stateTerminate)
  {
    /* Preset error to contain the success code */
    rc = errorNoError;
    
    /* Try to get a message from MLME */
    if(MSG_Pending(&mMlmeNwkInputQueue))
      pMsgIn = MSG_DeQueue(&mMlmeNwkInputQueue);
    else
      pMsgIn = NULL;
      
    switch(state)
    {
    case stateInit:
      /* Initialize the UART so that we can print out status messages */
      Uart_Init();
      /* Initialize the 802.15.4 stack */
      Init_802_15_4();
      /* Goto Energy Detection state. */
      state = stateScanActiveStart;

      /* Print a welcome message to the UART */
      Uart_Print("The Myapp_Ex03b demo application is initialized and ready.\n\n");
      break;
      
    case stateScanActiveStart:
      /* Start the Active scan, and goto wait for confirm state. */
      Uart_Print("Start scanning for a PAN coordinator\n");
      rc = App_StartScan(gScanModeActive_c);
      if(rc == errorNoError)
      {
        state = stateScanActiveWaitConfirm;
      }
      break;
      
    case stateScanActiveWaitConfirm:
      /* Stay in this state until the Scan confirm message
         arrives, and then goto the listen state. */
         
      /* ALWAYS free the beacon frame contained in the beacon notify indication.*/
      rc = App_WaitMsg(pMsgIn, gNwkBeaconNotifyInd_c);
      if(rc == errorNoError) {
        MSG_Free(((nwkMessage_t *)pMsgIn)->msgData.beaconNotifyInd.pBufferRoot);
        Uart_Print("Received an MLME-Beacon Notify Indication\n");
      }
      
      /* Handle the Scan Confirm message. */
      rc = App_WaitMsg(pMsgIn, gNwkScanCnf_c);
      if(rc == errorNoError)
      {
        rc = App_HandleScanActiveConfirm(pMsgIn);
        if(rc == errorNoError)
        {
          Uart_Print("Found a coordinator with the following properties:\n");
          Uart_Print("----------------------------------------------------");
          Uart_Print("\nAddress...........0x"); Uart_PrintHex(coordInfo.coordAddress, coordInfo.coordAddrMode == gAddrModeShort_c ? 2 : 8, 0);
          Uart_Print("\nPAN ID............0x"); Uart_PrintHex(coordInfo.coordPanId, 2, 0);
          Uart_Print("\nLogical Channel...0x"); Uart_PrintHex(&coordInfo.logicalChannel, 1, 0);
          Uart_Print("\nBeacon Spec.......0x"); Uart_PrintHex(coordInfo.superFrameSpec, 2, 0);
          Uart_Print("\nLink Quality......0x"); Uart_PrintHex(&coordInfo.linkQuality, 1, 0);
          Uart_Print("\n\n");

          state = stateListen;
        }
        else
          Uart_Print("Scan did not find a suitable coordinator\n");
      }
      break;
      
    case stateListen:
      /* Stay in this state forever. */
      break;
    }
    
    if(pMsgIn)
      /* ALWAYS free messages from MLME */
      MSG_Free(pMsgIn);
  
    /* Call the MAC main function. */
    macStatus = Mlme_Main();
  }
}


/******************************************************************************
* The App_StartScan(scanType) function will start the scan process of the
* specified type in the MAC. This is accomplished by allocating a MAC message,
* which is then assigned the desired scan parameters and sent to the MLME
* service access point.
* The function may return either of the following values:
*   errorNoError:          The Scan message was sent successfully.
*   errorInvalidParameter: The MLME service access point rejected the
*                          message due to an invalid parameter.
*   errorAllocFailed:      A message buffer could not be allocated.
*
******************************************************************************/
uint8_t App_StartScan(uint8_t scanType)
{
  mlmeMessage_t *pMsg;
  mlmeScanReq_t *pScanReq;

  Uart_Print("Sending the MLME-Scan Request message to the MAC...");

  /* Allocate a message for the MLME (We should check for NULL). */
  pMsg = MSG_AllocType(mlmeMessage_t);
  if(pMsg != NULL)
  {
    /* This is a MLME-START.req command */
    pMsg->msgType = gMlmeScanReq_c;
    /* Create the Start request message data. */
    pScanReq = &pMsg->msgData.scanReq;
    /* gScanModeED_c, gScanModeActive_c, gScanModePassive_c, or gScanModeOrphan_c */
    pScanReq->scanType = scanType;
    /* ChannelsToScan & 0xFF - LSB, always 0x00 */
    pScanReq->scanChannels[0] = (uint8_t)((SCAN_CHANNELS)     & 0xFF);
    /* ChannelsToScan>>8 & 0xFF  */
    pScanReq->scanChannels[1] = (uint8_t)((SCAN_CHANNELS>>8)  & 0xFF);
    /* ChannelsToScan>>16 & 0xFF  */
    pScanReq->scanChannels[2] = (uint8_t)((SCAN_CHANNELS>>16) & 0xFF);
    /* ChannelsToScan>>24 & 0xFF - MSB */
    pScanReq->scanChannels[3] = (uint8_t)((SCAN_CHANNELS>>24) & 0xFF);
    /* Duration per channel 0-14 (dc). T[sec] = (16*960*((2^dc)+1))/1000000.
       A scan duration of 5 on 16 channels approximately takes 8 secs. */
    pScanReq->scanDuration = 5;
    
    /* Send the Scan request to the MLME. */
    if(MSG_Send(NWK_MLME, pMsg) == gSuccess_c)
    {
      Uart_Print("Done\n");
      return errorNoError;
    }
    else
    {
      Uart_Print("Invalid parameter!\n");
      return errorInvalidParameter;
    }
  }
  else
  {
    /* Allocation of a message buffer failed. */
    Uart_Print("Message allocation failed!\n");
    return errorAllocFailed;
  }
}

/******************************************************************************
* The App_HandleScanActiveConfirm(nwkMessage_t *pMsg) function will handle the
* Active Scan confirm message received from the MLME when the Active scan has
* completed. The message contains a list of PAN descriptors. Based on link
* quality inforamtion in the pan descriptors the nearest coordinator is chosen.
* The corresponding pan descriptor is stored in the global variable coordInfo. 
*
* The function may return either of the following values:
*   errorNoError:       A suitable pan descriptor was found.
*   errorNoScanResults: No scan results were present in the confirm message.
*
******************************************************************************/
uint8_t App_HandleScanActiveConfirm(nwkMessage_t *pMsg)
{
  uint8_t panDescListSize   = pMsg->msgData.scanCnf.resultListSize;
  panDescriptor_t *pPanDesc = pMsg->msgData.scanCnf.resList.pPanDescriptorList;
  uint8_t rc = errorNoScanResults;
 
  /* Check if the scan resulted in any coordinator responses. */
  if(panDescListSize != 0)
  {
    /* Initialize link quality to very poor. */
    uint8_t i, bestLinkQuality = 0;
    
    /* Check all PAN descriptors. */
    for(i=0; i<panDescListSize; i++, pPanDesc++)
    {
      /* Only attempt to associate if the coordinator
         accepts associations and is non-beacon. */
      if( ( pPanDesc->superFrameSpec[1] & gSuperFrameSpecMsbAssocPermit_c) && 
          ((pPanDesc->superFrameSpec[0] & gSuperFrameSpecLsbBO_c) == 0x0F) )
      {
        /* Find the nearest coordinator using the link quality measure. */
        if(pPanDesc->linkQuality > bestLinkQuality)
        {
          /* Save the information of the coordinator candidate. If we
             find a better candiate, the information will be replaced. */
          memcpy(&coordInfo, pPanDesc, sizeof(panDescriptor_t));
          bestLinkQuality = pPanDesc->linkQuality;
          rc = errorNoError;
        }
      }
    }
  }
  /* ALWAYS free the PAN descriptor list */
  MSG_Free(pMsg->msgData.scanCnf.resList.pPanDescriptorList);
  
  return rc;
}


/******************************************************************************
* The App_WaitMsg(nwkMessage_t *pMsg, uint8_t msgType) function does not, as
* the name implies, wait for a message, thus blocking the execution of the
* state machine. Instead the function analyzes the supplied message to 
* determine whether or not the message is of the expected type.
* The function may return either of the following values:
*   errorNoError: The message was of the expected type.
*   errorNoMessage: The message pointer is NULL.
*   errorWrongConfirm: The message is not of the expected type.
*
******************************************************************************/
uint8_t App_WaitMsg(nwkMessage_t *pMsg, uint8_t msgType)
{
  /* Do we have a message? If not, the exit with error code */
  if(pMsg == NULL)
    return errorNoMessage;

  /* Is it the expected message type? If not then exit with error code */
  if(pMsg->msgType != msgType)
    return errorWrongConfirm;

  /* Found the expected message. Return with success code */
  return errorNoError;
}


/******************************************************************************
* The following functions are called by the MAC to put messages into the
* Application's queue. They need to be defined even if they are not used
* in order to avoid linker errors.
******************************************************************************/

uint8_t MLME_NWK_SapHandler(nwkMessage_t * pMsg)
{
  /* Put the incoming MLME message in the applications input queue. */
  MSG_Queue(&mMlmeNwkInputQueue, pMsg);
  return gSuccess_c;
}

uint8_t MCPS_NWK_SapHandler(mcpsToNwkMessage_t *pMsg)
{
  /* If the message is not handled anywhere it must be freed. */
  MSG_Free(pMsg);
  return gSuccess_c;
}

uint8_t ASP_APP_SapHandler(aspToAppMsg_t *pMsg)
{
  /* If the message is not handled anywhere it must be freed. */
  MSG_Free(pMsg);
  return gSuccess_c;
}