/******************************************************************************
Filename:     spp.c
Target:       cc2430
Revised:      16/12-2005
Revision:     1.0
******************************************************************************/
#include <string.h>
#include "cul.h"
#include <stdio.h>

// protos
void rxCallBack(void);
void ackTimeout(void);
BOOL ackReceived(BYTE sourceAddress);
void sendAck(SPP_RX_STRUCT* receivedPacket);
void waitForAck(void);


static DMA_DESC* dmaTx;          // pointer to the DMA descriptor for transmit.
static DMA_DESC* dmaRx;          // pointer to the DMA descriptor for receive.
static BYTE dmaNumberTx = 0;     // number indicating which DMA channel is used for transmit.
static BYTE dmaNumberRx = 0;     // number indicating which DMA channel is used for receive.
static BYTE myAddress;
volatile BYTE sppRxStatus = 0;
volatile BYTE  sppTxStatus = 0;
static BYTE pAckBuffer[7];
static SPP_TX_STRUCT* pAckData;
static volatile UINT8 retransmissionCounter;
static UINT8 ackTimerNumber;
static FUNCTION* rxCallBackFunction;


//-----------------------------------------------------------------------------
// See cul.h for a description of this function.
//-----------------------------------------------------------------------------
//設置用戶指定的回調函數，在接收到一個正確的數據包死運行
//通過這個函數可以用程序來改變正確接收數據包后的動作。
//callBackFunction 用戶指定的函數
//rxCallBackFunction 指向 FUNCTION 的全局變量指針變量
void sppSetRxCallBackFunction(FUNCTION* callBackFunction)
{
   rxCallBackFunction = callBackFunction;
} // Ends sppSetRxCallBackFunction()


//發送應答
//SPP_RX_STRUCT 定義在 cul.h
//SFR(  RFD       ,  0xD9  )   //  RF Data 定義在ioCC2430.h
// myAddress 全局變量
// ACK cul.h 中宏定義
// ISTXON hal.h 中宏定義
// srcAddress 源地址
void sendAck(SPP_RX_STRUCT* receivedPacket)
{
   RFD = SPP_HEADER_AND_FOOTER_LENGTH + SPP_ACK_LENGTH;
   RFD = receivedPacket->srcAddress;
   RFD = myAddress;
   RFD = ACK;
   RFD = 0;
   RFIF &= ~IRQ_TXDONE;
   ISTXON;
   while(!(RFIF & IRQ_TXDONE));

   return;
}

//------------------------------------------------------------------------------------------------------
// void rxCallBack(...)
//
//  Description:
//      This function is called by the interrupt routine when the Rx DMA channel
//      finishes the data transfer. The received packet's destination address
//      is checked. If not addressed to this node, or if the CRC value is not
//      correct, the packet is erased. An ACK is sent if the packet
//      tells to. A user defined callback function may is run if set (set
//      with setRxCallBackFunction())
//在Rx DAM  通道完成數據傳輸后由中斷程序調用。檢查接收包掉的目的地址，如果地址不是
//這個節點的，或CRC值是錯誤的，包裝將被擦除。如果數據包被告知將發送一個應答。一個用戶定義的回調函數可以運行如果定義了的話。
//  Arguments:
//      void
//
//  Return value:
//      void
//-----------------------------------------------------------------------------
//#define  RXFIFOCNT   XREG( 0xDF53 )  /*  Receive FIFO Count 定義在ioCC2430.h
// ISFLUSHRX 清 RX FIFO 命令濾波. hal.h 命令濾波中定義
// GET_DMA_DEST(dmaRx) hal.h 中的宏定義，取得一個 DMA 通道的目標地址
// static DMA_DESC* dmaRx 指向設備 DMA 描述符的指針，全局變量.DMA_DESC DMA 配置結構。
//
void rxCallBack(void)
{
   SPP_RX_STRUCT __xdata* receivedPacket;
   BYTE res = FALSE;

   if(RXFIFOCNT > 0)
   {
      ISFLUSHRX;
      ISFLUSHRX;
   }

   // Investigating the received packet.
   // Checking the destination address and that the CRC is OK.
   // The message is ACK'ed if it tells to.
   receivedPacket = (SPP_RX_STRUCT __xdata*) GET_DMA_DEST(dmaRx);
   receivedPacket->payloadLength = receivedPacket->payloadLength-SPP_HEADER_AND_FOOTER_LENGTH; //減去頭和尾長度

   if((receivedPacket->destAddress == myAddress) || (receivedPacket->destAddress == BROADCAST_ADDRESS)) //包目的地是本節點地址或廣播地址
   {
      if(receivedPacket->payload[receivedPacket->payloadLength+1] & 0x80)	//CRC正確
      {
         if(receivedPacket->flags == ACK)	//收到了應答包
         {
            res = ackReceived(receivedPacket->srcAddress);
         }
         else		//收到普通數據包
         {
            sppRxStatus = PACKET_RECEIVED;		//ssp接收狀態－收到數據包
            res = TRUE;
            if(receivedPacket->flags & DO_ACK)	//要求收到后發應答
            {
               sendAck(receivedPacket); 		//發應答
            }
            sppRxStatus = RX_COMPLETE;			//ssp接收狀態－接收完成
            if(rxCallBackFunction)
            {
               rxCallBackFunction();			//調用用戶指定回調函數
            }
         }
      }
   }

   if(res == FALSE)
   {
      ISFLUSHRX;	//清RX FIFO
      ISFLUSHRX;

      // rearming DMA channel
      DMA_ARM_CHANNEL(dmaNumberRx);
      RFIM |= IRQ_SFD;
      sppRxStatus = RX_WAIT;
   }
   return;
}   // ends rxCallBack




//-----------------------------------------------------------------------------
// void ackTimeout(...)
//
//  Description:
//      This function resends a packet if it is not ACK'ed by the recipient
//      within _ACK_TIMEOUT_ m-seconds. The message is resent _ACK_RETRIES_ times.
//      If the message remains un-ACK'ed, transmission is aborted and spp TX
//      status is set to DEST_UNREACHABLE.
//如果沒有收到接收器返回的應答，將重新發送數據包
//  Arguments:
//      void
//
//  Return value:
//      void
//-----------------------------------------------------------------------------
// TIMER4_RUN() 宏函數在 hal.h 中定義
// #define ACK_RETRIES  3 在 hal.h 中的宏定義常數
void ackTimeout(void){
   culTimer4AdmClear(ackTimerNumber);

   if(pAckData != NULL)
   {
      if(retransmissionCounter < ACK_RETRIES)	//重發次數小于嘗試接收應答次數
      {
         // Resending the message.
         pAckData->flags |= RETRANSMISSION;		//數據包標志－重發

         TIMER4_RUN(FALSE);						//停止定時器4

         sppSend(pAckData);						//發送數據包

         T4CNT = 0;								//定時器4計數清零
         TIMER4_RUN(TRUE);						//定時器4開始運行

         retransmissionCounter++;
      }
      else
      {
         // The packet has been resent too many times. Assuming that the node is unreacheble.
         pAckData = 0;
         retransmissionCounter = 0;
         sppTxStatus = DEST_UNREACHABLE;		//ssp發送狀態－不能完成
         RFIM &= ~IRQ_FIFOP;
      }
   }
   return;
} // ends ackTimeout




//-----------------------------------------------------------------------------
// See cul.h for a description of this function.
// 初始化簡單的數據包裝協議Simple Packet Protocol (SPP)
// 從 DMA 管理器申請兩個 DMA 通道，用于分別從 Rx FIFO 和 Tx FIFO 傳輸數據。定時器4
// 管理器同樣被設置，這個單元用于在數據包發送后接收器在一定時間內沒有返回應答時
// 產生中斷。無線部分配置為發送，工作在特定的頻率，在發送時自動計算和插入和檢查CRC值。
//-----------------------------------------------------------------------------
BOOL sppInit(UINT32 frequency, BYTE address){
   BYTE res = 0;
   BOOL status = TRUE;

   sppSetAddress(address);

   // Clearing the states of the spp.
   sppTxStatus = TX_IDLE;	//在 cul.h TX 和 RX 狀態標志部分宏定義
   sppRxStatus = RX_IDLE;	//同上
   retransmissionCounter = 0;
   ackTimerNumber = 0;
   pAckData = 0;

   // Clearing the RF interrupt flags and enable mask and enabling RF interrupts
   RFIF = 0;
   RFIM = 0;
   INT_SETFLAG(INUM_RF,INT_CLR);
   INT_ENABLE(INUM_RF,INT_ON);

   // Setting the frequency and initialising the radio
   res = halRfConfig(frequency); //在rfconfig.c
   if(res == FALSE){
      status = FALSE;
   }

   // Setting the number of bytes to assert the FIFOP flag
   IOCFG0 = 7;

   INT_SETFLAG(INUM_RFERR, INT_CLR);
   INT_ENABLE(INUM_RFERR, INT_ON);

   // Flushing both Tx and Rx FiFo. The flush-Rx is issued twice to reset the SFD.
   // Calibrating the radio and turning on Rx to evaluate the CCA.
   // SFD 開始幀定界符
   SRXON;
   SFLUSHTX;
   SFLUSHRX;
   SFLUSHRX;
   STXCALN;
   ISSTART;


   // Using the timer 4 administrator to generate interrupt to check if a message is unacked...
   culTimer4AdmInit();

   // Initialising the DMA administrator
   culDmaInit();

   // Requesting a DMA channel for transmit data. No callback function is used. Instead the TX_DONE
   // interrupt is used to determine when a transfer is finished. Configuring the DMA channel for
   // transmit. The data address and length will be set prior to each specific transmission.
   dmaTx = culDmaAllocChannel(&dmaNumberTx, 0);
   if((dmaNumberTx == 0) || (dmaNumberTx > 4)){
      status = FALSE;
   }

   culDmaToRadio(dmaTx, 0, 0, FALSE);

   // Requesting a DMA channel for receiving data. Giving the address of the callback function.
   // Configuring the DMA channel for receive. The data address will be set prior to each specific
   // reception.
   dmaRx = culDmaAllocChannel(&dmaNumberRx, &rxCallBack);
   if((dmaNumberRx == 0) || (dmaNumberRx > 4)){