AVRFreaks.net

#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>

#include "bma180.h"

#define F_CPU 8000000
 

#define sbi(var, mask)  ((var) |=(uint8_t)(1<<mask)) //Set bit
#define cbi(var, mask)   ((var) &=(uint8_t)~(1<<mask)) //clear

void SPI_Init(void)
{
sbi(SPCR,MSTR);
cbi(SPCR,SPR1);
sbi(SPCR,SPR0);
cbi(SPSR,SPI2X);
sbi(SPCR,SPE);
sbi(SPCR,CPOL);

sbi(SPCR,CPHA);
}



void txdata(char data)
{
   //while((SPSR&0x80) == 0x80);
   SPDR = data;
   while((SPSR&0x80) == 0x00);
}




char rxdata(void)
{
   //while((SPSR&0x80) == 0x80);
   SPDR = 0x55;
   while((SPSR&0x80) == 0x00);

   return SPDR;
}

#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>

#include "bma180.h"

#define F_CPU 8000000
 

#define sbi(var, mask)  ((var) |=(uint8_t)(1<<mask)) //Set bit
#define cbi(var, mask)   ((var) &=(uint8_t)~(1<<mask)) //clear

void SPI_Init(void)
{
sbi(SPCR,MSTR);
cbi(SPCR,SPR1);
sbi(SPCR,SPR0);
cbi(SPSR,SPI2X);
sbi(SPCR,SPE);
sbi(SPCR,CPOL);

sbi(SPCR,CPHA);
}

void txdata(char data)
{
   //while((SPSR&0x80) == 0x80);
   SPDR = data;
   while((SPSR&0x80) == 0x00);
}

char rxdata(void)
{
   //while((SPSR&0x80) == 0x80);
   SPDR = 0x55;
   while((SPSR&0x80) == 0x00);

   return SPDR;
}

char read(uint8_t address)
{
   //returns the contents of any 1 byte register from any address
   //sets the MSB for every address byte (READ mode)

   char byte;

   address |= 0x80;

   cbi(PORTB,4);
   txdata(address);
   byte = rxdata();
   sbi(PORTB,4);

   return byte;
}


void write(uint8_t address, char data)
{
   //write any data byte to any single address
   //adds a 0 to the MSB of the address byte (WRITE mode)

   address &= 0x7F;   

   //printf("\nWriting 0x% x to 0x% x\n", data, address);

   cbi(PORTB,4);
   _delay_ms(1);
   txdata(address);
   _delay_ms(1);
   txdata(data);
   _delay_ms(1);
   sbi(PORTB,4);
}

int init_BMA180(uint8_t range, uint8_t bw)
{
   char temp, temp1;
   
   // if connected correctly, ID register should be 3
   if(read(ID) != 3)
      return -1;
      
   //-------------------------------------------------------------------------------------
   // Set ee_w bit
   temp = read(CTRLREG0);
   temp |= 0x10;
   write(CTRLREG0, temp);   // Have to set ee_w to write any other registers
   //-------------------------------------------------------------------------------------
   // Set BW
   temp = read(BWTCS);
   temp1 = bw;
   temp1 = temp1<<4;
   temp &= (~BWMASK);
   temp |= temp1;
   write(BWTCS, temp);      // Keep tcs<3:0> in BWTCS, but write new BW
   //-------------------------------------------------------------------------------------
   // Set Range
   temp = read(OLSB1);
   temp1 = range;
   temp1 = (temp1<<RANGESHIFT);
   temp &= (~RANGEMASK);
   temp |= temp1;
   write(OLSB1, temp); //Write new range data, keep other bits the same
   //-------------------------------------------------------------------------------------
   
   return 0;
}

int main()
{
   SPI_Init();
   DDRB = 0;

   DDRB = (1<<2)|(1<<3)|(1<<5);
   DDRD = 0xFF;
   DDRC = 0xFF;
   init_BMA180(0x00, 0x00);

   while(1)
   {
      if(read(ID) != 3)
      {
      PORTD = 0xFF;
      PORTC= 0x00;
      }
      else
      {
      PORTD = 0x00;
      PORTC = 0xFF;
      }
   }
}   

   DDRB = (1<<2)|(1<<3)|(1<<5);