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Higher Priority on UART1

Peter Keller

How can I increase the interrupt priority of UART1 of the LPC2364?
Due to heavy load on timer interrupts, I'm missing receiving characters every 5 - 10 seconds.

The initialization of UART1 is as follow:

void enableUART1(void)
{
  VICVectAddr7  = (unsigned long) UART1_IRQHandler; // Set Interrupt Vector
  VICVectCntl7  = 17; //15;                         // use it for UART1 Interrupt
  VICIntEnable |= (1<<7);                           // Enable UART1 Interrupt
}


      // Enable RS485  P2.7 Initialisiert auf Out high
      PINSEL4 = PINSEL4|P2_00TXD1|P2_01RXD1;
      U1LCR   = bits|parity|stops|_DLABON;
      U1DLL   = (U8)baud;
      U1DLM   = (U8)(baud>>8);
      U1LCR   = bits|parity|stops|_DLABOFF;
      uart[_UART1].openChar1 =uart[_UART1].openChar2 =uart[_UART1].openChar3 =uart[_UART1].openChar4 =0;
      uart[_UART1].closeChar1=uart[_UART1].closeChar2=uart[_UART1].closeChar3=uart[_UART1].closeChar4=0;
      uart[_UART1].closeTimeout=timeout;
      flushBufferUART1( );
      U1IER   =(1<<0);        // Enable Rx Interrupt
      uart[_UART1].initialized=1;

Many thanks for any input.
Peter

Parents
  • 0 in reply to ImPer Westermark

    Per's comments are very correct. What you can do to calculate your timing budget is create a table that contains all the time consuming operations in your system in the form of period, duration, total cost. if you know that your system should do all its work within X[ms] (that is usually the least common multiple of all periods), then you can calculate a worst case scenario and the CPU load. this assumes of course a simple scheduling (non-preemptive).

Reply
  • 0 in reply to ImPer Westermark

    Per's comments are very correct. What you can do to calculate your timing budget is create a table that contains all the time consuming operations in your system in the form of period, duration, total cost. if you know that your system should do all its work within X[ms] (that is usually the least common multiple of all periods), then you can calculate a worst case scenario and the CPU load. this assumes of course a simple scheduling (non-preemptive).

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