spi.c

p89lpc915程序

#ifdef PH_932


#include <reg915.h>
#include "spi.h"
#include "message.h"

// flag to indicate if SPI is currently involved in a transfer or not
// stops a write to the SPI bus while a write is in progress
#define INFORMATION_CNT	4
#define DISC_TYPE_POSI	0
#define INPUT_MODE_POSI	1
#define SAMPLE_FREQ_POSI	2
#define WORD_LENGTH_POSI	3

static bit mspibusy;
bit spi_valid = 0;
char information[INFORMATION_CNT];
char spi_cnt = 0;
unsigned char spi_cmd = 0;
/***********************************************************************
DESC:    SPI Interrupt Service Routine
         Called when byte transmitted and/or byte received
         or if mode changed to slave by Slave Select pin
RETURNS: Nothing
************************************************************************/
void spi_isr () interrupt 9 using 3
{
  // clear SPIF bit by writing 1 to it
  SPSTAT |= 0x80;
  spi_cmd = SPDAT;
/*  spi_valid = 1;*/
/*
	while(RI == 1);
	SBUF = SPDAT;
	while(TI == 0);
	TI = 0;
*/
  // SPI not busy
  mspibusy = 0;
} // spi_isr

/***********************************************************************
DESC:    Initializes the SPI peripheral
         SPI Clock frequency = 250 kHz
         Set EA to 1 after calling
RETURNS: Nothing
************************************************************************/
void spi_init()
{
  // set MOSI, MISO, /SS and SPICLK as quasi-bidirectional
  P2M1 &= 0xC3;
  P2M2 &= 0xC3;

  // configure SPI
  SPCTL = 0x4C;

  // SPI initially not busy
  mspibusy = 0;

  // set SPI interrupt priority to 0
  IP1 &= ~0x08;
  IP1H &= ~0x08;

  // enable SPI interrupt
  ESPI = 1;
} // spi_init


#endif