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CC430F6137: Need help on receiver code so that red LED turns on when it is not receiving any transmitted packets

Part Number: CC430F6137

Hello,

I'm trying to modify the code so that when it is no longer receiving any transmitted data/packets it turns the red LED on and then when it starts to receive again it turns off the red LED. I'm using the CC430F6137 and the EM430F6137RF900 development tool kit and CCSv6. The code is modified based on the example code from the CC430 RF_toggle_LED_Demo.

#include "RF_Toggle_LED_Demo.h"

extern RF_SETTINGS rfSettings;

unsigned char packetReceived;
unsigned char packetTransmit; 

unsigned char txBytesLeft = PACKET_LEN;           // +1 for length byte 
unsigned char txPosition = 0; 
unsigned char rxBytesLeft = PACKET_LEN+2;         // +2 for status bytes
unsigned char rxPosition = 0;
unsigned char lengthByteRead = 0; 

unsigned char RxBufferLength = 0;
unsigned char TxBufferLength = 0; 
unsigned char * _p_Buffer = 0; 
unsigned char buttonPressed = 0;
unsigned int i = 0;                 

unsigned char transmitting = 0; 
unsigned char receiving = 0; 

unsigned char RxBuffer[PACKET_LEN+2] = {0};
unsigned char TxBuffer[PACKET_LEN]= {
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 
    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 
    0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 
    0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 
    0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 
    0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 
    0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 
    0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 
    0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 
    0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 
};

void main( void )
{  
  // Stop watchdog timer to prevent time out reset 
  WDTCTL = WDTPW + WDTHOLD; 
    
  // Increase PMMCOREV level to 2 for proper radio operation
  SetVCore(2);                               
  
  ResetRadioCore();
  InitButtonLeds();
  InitTimer(); 
    
  // Clean out the RX Buffer 
  rxPosition = PACKET_LEN+2;
  while(rxPosition--)
  {
    RxBuffer[rxPosition] = 0; 
  }

  InitRadio();  
  ReceiveOn(); 
    
  while (1)
  {    
    __bis_SR_register( LPM3_bits + GIE );   
    __no_operation(); 
   
    if(receiving)
    {
      ReceivePacket(); 
      __no_operation(); 
    }
    if(!transmitting)
    {
      ReceiveOn(); 
    }
  }
}

void ReceivePacket(void)
{
  rxBytesLeft = PACKET_LEN + 2;// Set maximum packet leng + 2 for appended bytes
  rxPosition = 0; 
  packetReceived = 0; 
  
  __delay_cycles(2800);                     // Wait for bytes to fill in RX FIFO

  TA0CCR1   = RX_TIMER_PERIOD;              // x cycles * 1/32768 = y us
  TA0CCTL1 |= CCIE;            
  TA0CTL   |= MC_2 + TACLR;                 // Start the timer- continuous mode

  __bis_SR_register(LPM3_bits + GIE); 
  __no_operation(); 
  
  TA0CCR1 = RX_TIMER_PERIOD;             
  TA0CCTL1 &= ~(CCIE);
  TA0CTL &= ~(MC_3);                  // Turn off timer 
  
  __no_operation(); 
}


void ReceiveOn(void)
{  
  RF1AIES &= ~BIT9; 
  RF1AIFG = 0;                              // Clear pending RFIFG interrupts
  RF1AIE  |= BIT9;                          // Enable the sync word received interrupt
  
  // Radio is in IDLE following a TX, so strobe SRX to enter Receive Mode
  Strobe( RF_SRX );        
  
  __no_operation(); 
}

void ReceiveOff(void)
{
  RF1AIE &= ~BIT9;                          // Disable RX interrupts
  RF1AIFG &= ~BIT9;                         // Clear pending IFG
  RF1AIES &= ~BIT9;                         // Switch back to to sync word

  // It is possible that ReceiveOff is called while radio is receiving a packet.
  // Therefore, it is necessary to flush the RX FIFO after issuing IDLE strobe 
  // such that the RXFIFO is empty prior to receiving a packet.
  Strobe(RF_SIDLE); 
  Strobe(RF_SFRX);                       
}

//------------------------------------------------------------------------------
//  void pktRxHandler(void)
//
//  DESCRIPTION:
//      This function is called every time a timer interrupt occurs. The 
//      function starts by retreiving the status byte. Every time the status 
//      byte indicates that there are available bytes in the RX FIFO, bytes are 
//      read from the RX FIFO and written to RxBuffer. This is done until the 
//      whole packet is received. If the status byte indicates that there has 
//      been an RX FIFO overflow the RX FIFO is flushed. Please see the 
//      EM430F6137RF900 RF Examples User Manual for a flow chart describing this 
//      function.
//------------------------------------------------------------------------------
void pktRxHandler(void) {
  unsigned char RxStatus;
  unsigned char bytesInFifo;
  
  // Which state?
  RxStatus = Strobe(RF_SNOP);
  
  switch(RxStatus & CC430_STATE_MASK)
  {
    case CC430_STATE_RX:
      // If there's anything in the RX FIFO....
      if (bytesInFifo = MIN(rxBytesLeft, RxStatus & CC430_FIFO_BYTES_AVAILABLE_MASK))
      {         
        // Update how many bytes are left to be received
        rxBytesLeft -= bytesInFifo;
  
        // Read from RX FIFO and store the data in rxBuffer
        while (bytesInFifo--) {
          RxBuffer[rxPosition] = ReadSingleReg(RXFIFO);
          rxPosition++; 
        }  
        if (!rxBytesLeft){           
            packetReceived = 1; 
            receiving = 0;
            lengthByteRead = 0; 
            ReceiveOff();
            
            P1OUT ^= BIT0;                    // Toggle LED1             
        }      
      } 
      break;
    default:
      if(!packetReceived)
      {
        packetReceived = 1; 
      }
      
      rxBytesLeft = 0;
      receiving = 0; 
      ReceiveOff();

      break;  
  }
} // pktRxHandler

//------------------------------------------------------------------------------
//  void pktTxHandler(void)
//
//  DESCRIPTION:
//      This function is called every time a timer interrupt occurs. The function starts
//      by getting the status byte. Every time the status byte indicates that there 
//      is free space in the TX FIFO, bytes are taken from txBuffer and written to 
//      the TX FIFO until the whole packet is written or the TXFIFO has underflowed. 
//      See the EM430F6137RF900 RF Examples User Manual for a flow chart describing 
//      this function.
//------------------------------------------------------------------------------
void pktTxHandler(void) {
    unsigned char freeSpaceInFifo;
    unsigned char TxStatus;  
    
    // Which state?
    TxStatus = Strobe(RF_SNOP);

    switch (TxStatus & CC430_STATE_MASK) {
        case CC430_STATE_TX:
            // If there's anything to transfer..
            if (freeSpaceInFifo = MIN(txBytesLeft, TxStatus & CC430_FIFO_BYTES_AVAILABLE_MASK)) 
            {
              txBytesLeft -= freeSpaceInFifo;

              while(freeSpaceInFifo--)
              {
                WriteSingleReg(TXFIFO, TxBuffer[txPosition]);
                txPosition++; 
              }
              
              if(!txBytesLeft)
              {                
                RF1AIES |= BIT9;      // End-of-packet TX interrupt
                RF1AIFG &= ~BIT9;     // clear RFIFG9
                while(!(RF1AIFG & BIT9)); // poll RFIFG9 for TX end-of-packet  
                RF1AIES &= ~BIT9;      // End-of-packet TX interrupt
                RF1AIFG &= ~BIT9;     // clear RFIFG9
                transmitting = 0; 
                packetTransmit = 1; 
              }
            }
            break;

        case CC430_STATE_TX_UNDERFLOW:
            Strobe(RF_SFTX);  // Flush the TX FIFO
            
            __no_operation(); 
            // No break here!
        default:
            if(!packetTransmit) 
              packetTransmit = 1; 
            
            if (transmitting) {
                if ((TxStatus & CC430_STATE_MASK) == CC430_STATE_IDLE) {
    	          transmitting = 0; 
                }
            }
        break;
    }
} // pktTxHandler

void InitTimer(void)
{
  P5SEL |= 0x03;                            // Set xtal pins  
  LFXT_Start(XT1DRIVE_0); 
  
  TA0CCR1  = RX_TIMER_PERIOD;               // x cycles * 1/32768 = y us
  TA0CCTL1 = CCIE;                          // Enable interrupts
  TA0CTL   = TASSEL__ACLK + TACLR;          // ACLK source
}

void InitButtonLeds(void)
{
  // Set up the button as interruptible 
  P1DIR &= ~BIT7;
  P1REN |= BIT7;
  P1IES &= BIT7;
  P1IFG = 0;
  P1OUT |= BIT7;
  P1IE  |= BIT7; 

  // Initialize Port J
  PJOUT = 0x00;
  PJDIR = 0xFF; 

  // Set up LEDs 
  P1OUT &= ~BIT0;
  P1DIR |= BIT0;
  P3OUT &= ~BIT6;
  P3DIR |= BIT6;
}

void InitRadio(void)
{
  // Set the High-Power Mode Request Enable bit so LPM3 can be entered
  // with active radio enabled 
  PMMCTL0_H = 0xA5;
  PMMCTL0_L |= PMMHPMRE_L; 
  PMMCTL0_H = 0x00; 
  
  WriteRfSettings(&rfSettings);
  
  WriteSinglePATable(PATABLE_VAL);
}

/**************************************
* Interrupt Service Routines
**************************************/

#pragma vector=TIMER0_A1_VECTOR
__interrupt void TIMER0_A1_ISR(void)
{
  switch(__even_in_range(TA0IV,14))
  {
    case 0:  break;                  
    case 2:  
      if(receiving)
      {
        TA0CCR1 += RX_TIMER_PERIOD;                  // 16 cycles * 1/32768 = ~500 us

        pktRxHandler();  
        
        if(packetReceived)
          __bic_SR_register_on_exit(LPM3_bits); 
      }
      else if(transmitting)
      {
        TA0CCR1 += TX_TIMER_PERIOD;                  // 16 cycles * 1/32768 = ~500 us

        pktTxHandler(); 
        
        if(packetTransmit)
          __bic_SR_register_on_exit(LPM3_bits); 
      }       
      break;
    case 4:  break;                         // CCR2 not used
    case 6:  break;                         // Reserved not used
    case 8:  break;                         // Reserved not used
    case 10: break;                         // Reserved not used
    case 12: break;                         // Reserved not used
    case 14: break;                         // Overflow not used
  }
}

#pragma vector=CC1101_VECTOR
__interrupt void CC1101_ISR(void)
{
  switch(__even_in_range(RF1AIV,32))        // Prioritizing Radio Core Interrupt 
  {
    case  0: break;                         // No RF core interrupt pending                                            
    case  2: break;                         // RFIFG0 
    case  4: break;                         // RFIFG1
    case  6: break;                         // RFIFG2
    case  8: break;                         // RFIFG3
    case 10: break;                         // RFIFG4
    case 12: break;                         // RFIFG5
    case 14: break;                         // RFIFG6          
    case 16: break;                         // RFIFG7
    case 18: break;                         // RFIFG8
    case 20:                                // RFIFG9
      if(!(RF1AIES & BIT9))                 // RX sync word received 
      {
        receiving = 1;         
        __bic_SR_register_on_exit(LPM3_bits); // Exit active    
      }	   
      else while(1); 			    // trap 
      break;
    case 22: break;                         // RFIFG10
    case 24: break;                         // RFIFG11
    case 26: break;                         // RFIFG12
    case 28: break;                         // RFIFG13
    case 30: break;                         // RFIFG14
    case 32: break;                         // RFIFG15
  }      
}

  • "when it is no longer receiving any transmitted data/packets ..."

    rather than writing a bunch of code to get it done, why don't you pick up the datasheet and see if the uart offers such possibility.

    My quick glance tells me it is not doable with that chip but who am I to tell you that?

    with that said, you may find it much easier to simply hang a led to the RX line. no code needed.

  • Thanks for the reply, going to try that out.

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