www.pudn.com > CC2420_TRX.rar > basic_rf_send_packet.c

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 *      ***   +++   ***                                                                                * 
 *      ***   + +   ***                                                                                * 
 *      ***   +                               CHIPCON CC2420 BASIC RF LIBRARY                          * 
 *      ***   + +   ***                             Packet transmission                                * 
 *      ***   +++   ***                                                                                * 
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 * This file contains packet transmission function.                                                    * 
 *                                                                                                     * 
 * More information can be found in basic_rf.h                                                         * 
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 * Compiler: AVR-GCC                                                                                   * 
 * Target platform: CC2420DB, CC2420 + any MCU with very few modifications required                    * 
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 * Revision history:                                                                                   * 
 *  $Log: basic_rf_send_packet.c,v $ 
 *  Revision 1.4  2004/07/26 11:28:10  mbr 
 *  Modified RXFIFO flushing by strobing CC2420_SFLUSHRX 
 * 
 *  Revision 1.3  2004/03/30 14:59:22  mbr 
 *  Release for web 
 *  
 * 
 * 
 *******************************************************************************************************/ 
#include  
 
 
 
 
//------------------------------------------------------------------------------------------------------- 
//  BYTE basicRfSendPacket(BASIC_RF_TX_INFO *pRTI) 
// 
//  DESCRIPTION: 
//		Transmits a packet using the IEEE 802.15.4 MAC data packet format with short addresses. CCA is 
//		measured only once before backet transmission (not compliant with 802.15.4 CSMA-CA). 
//		The function returns: 
//			- When pRTI->ackRequest is FALSE: After the transmission has begun (SFD gone high) 
//			- When pRTI->ackRequest is TRUE: After the acknowledgment has been received/declared missing. 
//		The acknowledgment is received through the FIFOP interrupt. 
// 
//  ARGUMENTS: 
//      BASIC_RF_TX_INFO *pRTI 
//          The transmission structure, which contains all relevant info about the packet. 
// 
//  RETURN VALUE: 
//		BOOL 
//			Successful transmission (acknowledgment received) 
//------------------------------------------------------------------------------------------------------- 
BOOL basicRfSendPacket(BASIC_RF_TX_INFO *pRTI) { 
	WORD frameControlField; 
    UINT8 packetLength; 
    BOOL success; 
    BYTE spiStatusByte; 
 
    // Wait until the transceiver is idle 
    while (FIFOP_IS_1 || SFD_IS_1); 
 
    // Turn off global interrupts to avoid interference on the SPI interface 
    DISABLE_GLOBAL_INT(); 
 
	// Flush the TX FIFO just in case... 
	FASTSPI_STROBE(CC2420_SFLUSHTX); 
 
    // Turn on RX if necessary 
    if (!rfSettings.receiveOn) FASTSPI_STROBE(CC2420_SRXON); 
 
    // Wait for the RSSI value to become valid 
    do { 
        FASTSPI_UPD_STATUS(spiStatusByte); 
    } while (!(spiStatusByte & BM(CC2420_RSSI_VALID))); 
 
	// TX begins after the CCA check has passed 
    do { 
		FASTSPI_STROBE(CC2420_STXONCCA); 
		FASTSPI_UPD_STATUS(spiStatusByte); 
		halWait(100); 
    } while (!(spiStatusByte & BM(CC2420_TX_ACTIVE))); 
 
    // Write the packet to the TX FIFO (the FCS is appended automatically when AUTOCRC is enabled) 
    packetLength = pRTI->length + BASIC_RF_PACKET_OVERHEAD_SIZE; 
    FASTSPI_WRITE_FIFO((BYTE*)&packetLength, 1);               // Packet length 
    frameControlField = pRTI->ackRequest ? BASIC_RF_FCF_ACK : BASIC_RF_FCF_NOACK; 
    FASTSPI_WRITE_FIFO((BYTE*) &frameControlField, 2);         // Frame control field 
    FASTSPI_WRITE_FIFO((BYTE*) &rfSettings.txSeqNumber, 1);    // Sequence number 
    FASTSPI_WRITE_FIFO((BYTE*) &rfSettings.panId, 2);          // Dest. PAN ID 
    FASTSPI_WRITE_FIFO((BYTE*) &pRTI->destAddr, 2);            // Dest. address 
    FASTSPI_WRITE_FIFO((BYTE*) &rfSettings.myAddr, 2);         // Source address 
	FASTSPI_WRITE_FIFO((BYTE*) pRTI->pPayload, pRTI->length);  // Payload 
 
	// Wait for the transmission to begin before exiting (makes sure that this function cannot be called 
	// a second time, and thereby cancelling the first transmission (observe the FIFOP + SFD test above). 
	while (!SFD_IS_1); 
	success = TRUE; 
 
	// Turn interrupts back on 
	ENABLE_GLOBAL_INT(); 
 
    // Wait for the acknowledge to be received, if any 
    if (pRTI->ackRequest) { 
		rfSettings.ackReceived = FALSE; 
 
		// Wait for the SFD to go low again 
		while (SFD_IS_1); 
 
        // We'll enter RX automatically, so just wait until we can be sure that the ack reception should have finished 
        // The timeout consists of a 12-symbol turnaround time, the ack packet duration, and a small margin 
        halWait((12 * BASIC_RF_SYMBOL_DURATION) + (BASIC_RF_ACK_DURATION) + (2 * BASIC_RF_SYMBOL_DURATION) + 100); 
 
		// If an acknowledgment has been received (by the FIFOP interrupt), the ackReceived flag should be set 
		success = rfSettings.ackReceived; 
    } 
 
	// Turn off the receiver if it should not continue to be enabled 
    DISABLE_GLOBAL_INT(); 
	if (!rfSettings.receiveOn) FASTSPI_STROBE(CC2420_SRFOFF); 
    ENABLE_GLOBAL_INT(); 
 
    // Increment the sequence number, and return the result 
    rfSettings.txSeqNumber++; 
    return success; 
 
} // halRfSendPacket