Lpc2000

--- In lpc2000@yahoogroups.com, Sten <list@n...> wrote:
>
> ee_gary wrote:
> > Long time lurker, first time poster...
> > 
> > I've set the SPIE bit in the Control Register.  I can see the SPIF bit
> > get set in the Status Register.  However, I do NOT see the SPI
> > Interrupt bit get set in the Interrupt Register.  Shouldn't this occur
> > as soon as the SPIF bit is set, regardless of how the VIC is set up? 
> > I have the VIC set up "correctly", but the ISR never executes
> > (presumably because the SPI Interrupt never fires).  I've had
> > interrupts working correctly for UART0 and a timer, so I know that
> > interrupts can work (they just aren't in this occasion).
> > 
> > I can do non-interrupt SPI transmits (i.e. the 1st byte of an
> > interrupt-based multibye transfer) so I know the hardware is ok (SSEL
> > = 1).  I've duplicated this on the MCB2130 and a LPC2214 dev board.
> > 
> > Any insight from those that have implemented interrupt based SPI is
> > appreciated.
> > 
> > Stumped in Seattle...
> > 
> 
> Please can you send a small portion of source code? It sounds
unbelievable.
> 
>   Sten
> 
> -- 
> /************************************************
>  Do you need a tiny and efficient real time
>  operating system (RTOS) with a preemtive
>  multitasking for LPC2000 or AT91SAM7?
> 
>    http://nanortos.net-attack.de/
> 
>  Or some open-source tools and code for LPC2000?
> 
>    http://www.net-attack.de/
> 
> ************************************************/
>

It'd be my pleasure.  Here's the init function:
void spi0Init(void)
{
  // Set port pins for SPI0
  PINSEL0 = (PINSEL0 & ~S0_PINMASK) | S0_PINSEL;

  // Set SPI Registers
  S0SPCR = 0;           // Clear all bits
  S0SPCR |= SPCR_CPHA;  // Data sampled on rising edge
  S0SPCR |= SPCR_CPOL;	// SCK active low
  S0SPCR |= SPCR_MSTR;	// Master mode

  S0SPSR;         // Cleared by a read of this register
  S0SPDR;         // Cleared by a read of this register
  S0SPCCR = 128;  // 8 is max speed
  S0SPINT = 1;    // Cleared by writing a 1 to it

  // initialize the interrupt vector
  VICIntSelect = 0;  // Select IRQ
  VICIntEnable = 0x00000400;
  VICVectAddr0 = (unsigned long)spi0ISR;
  VICVectCntl0 = 0x0000002A;
									
  // initialize the transmit data queue
  spi0_tx_extract_idx = spi0_tx_insert_idx = 0;
  spi0_tx_running = 0;
}

and the transmit function:
int spi0Putch(int ch)
{
  uint16_t temp;
  unsigned cpsr;

  temp = (spi0_tx_insert_idx + 1) % SPI0_TX_BUFFER_SIZE;

  if (temp == spi0_tx_extract_idx)
    return -1;                          // no room

  cpsr = disableIRQ();                  // disable global interrupts
  S0SPCR &= ~SPCR_SPIE;                 // disable TX interrupts
  restoreIRQ(cpsr);                     // restore global interrupts

  // check if in process of sending data
  if (spi0_tx_running){
    // add to queue
    spi0_tx_buffer[spi0_tx_insert_idx] = (uint8_t)ch;
    spi0_tx_insert_idx = temp;
  }
  else{
    // set running flag and write to output register    
    spi0_tx_running = 1;
    S0SPDR = (uint8_t)ch;
  }
  cpsr = disableIRQ();                  // disable global interrupts
  S0SPCR |= SPCR_SPIE;                  // enable TX interrupts
  restoreIRQ(cpsr);                     // restore global interrupts

  return (uint8_t)ch;
}

and finally, the ISR that never fires...
void spi0ISR(void)
{
  // perform proper ISR entry so thumb-interwork works properly
  ISR_ENTRY();

  // check if more data to send
  if (spi0_tx_insert_idx != spi0_tx_extract_idx){
    S0SPDR = spi0_tx_buffer[spi0_tx_extract_idx++];
    spi0_tx_extract_idx %= SPI0_TX_BUFFER_SIZE;
  }
  else{ // No more to transmit
    S0SPCR &= ~SPCR_SPIE;
    spi0_tx_running = 0;
  }
  
  S0SPINT = 1;  
  VICVectAddr = 0x00000000;   

  ISR_EXIT();
}

It seems like it should be something simple.  Everything looks okay,
but the ISR never fires.

Thanks,

Gary