rf_receive.c

CC2420+PIC单片机基础实验代码、CC2420无线收发实验代码

#include <include.h>
extern volatile BASIC_RF_SETTINGS rfSettings;
extern void halWait(UINT16 timeout);
extern BASIC_RF_RX_INFO* basicRfReceivePacket(BASIC_RF_RX_INFO *pRRI);
//-------------------------------------------------------------------------------------------------------
//  void halRfReceiveOn(void)
//
//  DESCRIPTION:
//      Enables the CC2420 receiver and the FIFOP interrupt. When a packet is received through this
//      interrupt, it will call halRfReceivePacket(...), which must be defined by the application
//-------------------------------------------------------------------------------------------------------
void basicRfReceiveOn(void) {
    rfSettings.receiveOn = TRUE;
	FASTSPI_STROBE(CC2420_SRXON);
	FASTSPI_STROBE(CC2420_SFLUSHRX);
	FIFOP_INT_INIT();
    ENABLE_FIFOP_INT();
} // basicRfReceiveOn




//-------------------------------------------------------------------------------------------------------
//  void halRfReceiveOff(void)
//
//  DESCRIPTION:
//      Disables the CC2420 receiver and the FIFOP interrupt.
//-------------------------------------------------------------------------------------------------------
void basicRfReceiveOff(void) {
    rfSettings.receiveOn = FALSE;
	FASTSPI_STROBE(CC2420_SRFOFF);
    DISABLE_FIFOP_INT();
} // basicRfReceiveOff

//-------------------------------------------------------------------------------------------------------
//  SIGNAL(SIG_INTERRUPT0) - CC2420 FIFOP interrupt service routine
//
//  DESCRIPTION:
//		When a packet has been completely received, this ISR will extract the data from the RX FIFO, put
//		it into the active BASIC_RF_RX_INFO structure, and call basicRfReceivePacket() (defined by the
//		application). FIFO overflow and illegally formatted packets is handled by this routine.
//
//      Note: Packets are acknowledged automatically by CC2420 through the auto-acknowledgment feature.
//-------------------------------------------------------------------------------------------------------

///******************************************************************************
// Interrupt Vectors
//******************************************************************************
void HighISR();
#pragma code high_vector=0x08
 void high_interrupt (void)
 {
	 _asm GOTO HighISR _endasm
 }
#pragma code
#pragma interruptlow HighISR
void HighISR()
{
	WORD frameControlField;
	INT8 length;
	BYTE pFooter[2];
    
    CLEAR_FIFOP_INT();
    // Clean up and exit in case of FIFO overflow, which is indicated by FIFOP = 1 and FIFO = 0
	if((FIFOP_IS_1) && (!(FIFO_IS_1))) {	   
	    FASTSPI_STROBE(CC2420_SFLUSHRX);
	    FASTSPI_STROBE(CC2420_SFLUSHRX);
	    return;
	}

	// Payload length
	FASTSPI_READ_FIFO_BYTE(length);
	
	length &= BASIC_RF_LENGTH_MASK; // Ignore MSB

    // Ignore the packet if the length is too short
    if (length < BASIC_RF_ACK_PACKET_SIZE) {
    	FASTSPI_READ_FIFO_GARBAGE(length);

    // Otherwise, if the length is valid, then proceed with the rest of the packet
    } else {
        // Register the payload length
        rfSettings.pRxInfo->length = length - BASIC_RF_PACKET_OVERHEAD_SIZE;

        // Read the frame control field and the data sequence number
        FASTSPI_READ_FIFO_NO_WAIT((BYTE*) &frameControlField, 2);
        rfSettings.pRxInfo->ackRequest = !!(frameControlField & BASIC_RF_FCF_ACK_BM);
    	FASTSPI_READ_FIFO_BYTE(rfSettings.pRxInfo->seqNumber);

		// Is this an acknowledgment packet?
    	if ((length == BASIC_RF_ACK_PACKET_SIZE) && (frameControlField == BASIC_RF_ACK_FCF) && (rfSettings.pRxInfo->seqNumber == rfSettings.txSeqNumber)) {

 	       	// Read the footer and check for CRC OK
			FASTSPI_READ_FIFO_NO_WAIT((BYTE*) pFooter, 2);

			// Indicate the successful ack reception (this flag is polled by the transmission routine)
			if (pFooter[1] & BASIC_RF_CRC_OK_BM) rfSettings.ackReceived = TRUE;
 
		// Too small to be a valid packet?
		} else if (length < BASIC_RF_PACKET_OVERHEAD_SIZE) {
			FASTSPI_READ_FIFO_GARBAGE(length - 3);
			return;

		// Receive the rest of the packet
		} 
		else 
		{

			// Skip the destination PAN and address (that's taken care of by harware address recognition!)
			FASTSPI_READ_FIFO_GARBAGE(4);

			// Read the source address
			FASTSPI_READ_FIFO_NO_WAIT((BYTE*) &rfSettings.pRxInfo->srcAddr, 2);

			// Read the packet payload
			FASTSPI_READ_FIFO_NO_WAIT(rfSettings.pRxInfo->pPayload, rfSettings.pRxInfo->length);
    		
			// Read the footer to get the RSSI value
			FASTSPI_READ_FIFO_NO_WAIT((BYTE*) pFooter, 2);
			rfSettings.pRxInfo->rssi = pFooter[0];

			// Notify the application about the received _data_ packet if the CRC is OK
			if (((frameControlField & (BASIC_RF_FCF_BM)) == BASIC_RF_FCF_NOACK) && (pFooter[1] & BASIC_RF_CRC_OK_BM)) {
				rfSettings.pRxInfo = basicRfReceivePacket(rfSettings.pRxInfo);
			}
		}
    }

} // SIGNAL(SIG_INTERRUPT0)