Lpc2000

Hi Fredrik,

there are 2 things in your code that may cause problems :

1) You don't read the frame status register(CANRFS), so you loose the information if it is a 11-bit or a 29 bit identifier as well as the data length information and the remote request bit.

2) It is written in the comment but not done : release the buffer. To do this, you have to write 1 to bit2 in the command register (CANCMR)

brgds
Klaus

-----Ursprüngliche Nachricht-----
Von: lpc2000@yahoogroups.com im Auftrag von albin_martinsson
Gesendet: Do 15.09.2005 15:35
An: lpc2000@yahoogroups.com
Betreff: [lpc2000] CAN DOIE
 
Hello

Im using the CAN-interface in my application. 
My routine for CAN is interrupt-driven, here is an example of my ISR-
code:

I often get Data Overrun - error on the receive channel.
Anyone who has had the same problem? 
I also use the freeRTOS port for the LPC2129. 

B.R

Fredrik Martinsson, Sweden

void ISR_CANRX (void)
{
   tU32 *cBufdst;
   tU32 Buf[3];

   while (C1GSR&0x01) {
      // Save registers temp.
      Buf[0] = C1RID;
      Buf[1] = C1RDA;
      Buf[2] = C1RDB;
      C1CMR = 0x04;                               
      // release receive buffer
            
            
      if (++can_rxbufin>=CAN_QUEUESIZE)can_rxbufin = 0;
      cBufdst = &can_rxbuf[can_rxbufin].CmRID;
                  
      if (can_rxbufin == can_rxbufout) {
         if (++can_rxbufout>=CAN_QUEUESIZE)can_rxbufout = 0;
      }
      if (++can_rxbufsize>CAN_QUEUESIZE)
can_rxbufsize=CAN_QUEUESIZE;
                  
      *cBufdst = Buf[0];
      cBufdst++;
      *cBufdst = Buf[1];
      cBufdst++;
      *cBufdst = Buf[2];
                  
      // Give semaphore to start comTask
      xSemaphoreGiveFromISR( comSem, pdFALSE );
      }
      
   VICVectAddr = 0xFFFFFFFFL;                         
   // acknowledge Interrupt
}






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