Lpc2000

Adding a read of the status register (SPSR) to the ISR solves the 
problem.  Now to figure out why.......


Richard

--- In lpc2000@yahoogroups.com, "Richard" <richas@y...> wrote:
> 
> I am putting togther simple SPI routines using an interrupt.  What 
I 
> am see is that, if I put a breakpoint in the SPI ISR, I see the 
byte 
> get spit out and the program breaks where it ought to.  
> Pressing "go" repeatadly sends out more bytes.  If I remove the 
> breakpoint I expect to see repeated bytes sent out but, alas, I do 
> not, I see one byte transmitted and the PC is in the delay loop 
went 
> I stop execution.
> 
> Keil uVision 3 (Using the KEIL ARM compiler)
> Ulink
> IAR Kickstart board
> 
> Thanks for the help
> 
> Richard
> 
> 
> Code:
> 
> void VIC_setup (void)  {
> 
>   /* The SPI Interrupt is an IRQ   */
>   VICIntSelect   &= ~0x400;
>   /* Use slot 0 for SPI Interrupt  */
>   VICVectCntl0 = 0x2A;
>   /* Set address for of ISR in slot 0  */
>   VICVectAddr0 = (unsigned long)SPI_IRQ;
>   /* Enable SPI Interrupt  */			
>   VICIntEnable   = 0x400;			
> }
> 
> void SPI_IRQ (void) __irq {
> 
>   SPI_data = SPDR;		//read data register		
> 			
>   SPINT        = 1;                         // Clear interrupt flag
>   VICVectAddr = 0;                         // Acknowledge Interrupt
> 
> }
> 
> void SPI_setup (void)	
> 	{
> 		SPCCR = 200; 	//  spi rate
> 		SPCR = 0xA0;	// master mode, interrupt enabled
> 		dummy = SPSR;
> 	}
> void IO_setup (void)//
> 	{
> 		IODIR = 0xff; // P0.0..7 defined as Outputs
> 	    PINSEL0 = 0x5500; // enable spi i/o	
> 	}
> 
>  unsigned char SPI_tfr(unsigned char SPI_data)
>  	{
> 		unsigned char val;
> 
> 		SPDR = SPI_data;
> 	
> 	}
> 
> 
> int main (void) {
> 
> unsigned char pin;
> unsigned long i;
> 
> 	SPI_setup();
> 	IO_setup();
> 	VIC_setup();
>  
> 	pin = 0;
> 
> 	while (1) {
>  
> //	if (pin) IOSET = 0x20; else IOCLR = 0x20;
> 
> //	pin ^= 1;
> 	SPI_tfr(0xAA);
> 	for(i=0; i<3000; i++);	  //kill some time to allow SPI 
> interrupt
> 	
> 	
> 
> 	}
> }