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Dear frens,

I am using digital accelerometer with PIC18f452 to read data of
acceleration through spi interface.

Here I am getting problem in writing conversion command for three axis
accelerations into digital output.

I am new to embedded but I have written a C program by referring from
datasheet of accelerometer.

I am writing the code here so any one tell me where I went wrong and
help me please.

[code]

#include<18f452.h>
#include
#use delay (clock=6000000)
#use rs232 ( baud= 9600, xmit=PIN_C6, rcv= PIN_C7 )
#include

//#device PIC18F452
//#include
//#define spi_master 0x20
//#define spi_slave 0x24
//#include
#define FF_int_w 0x06
#define FF_delay_w 0x07
#define MOT_int_w 0x08
#define MOT_delay_w 0x09
#define FF_int_r 0x86
#define FF_delay_r 0x87
#define MOT_int_r 0x88
#define MOT_delay_r 0x89
#define XOUT_H 0x80
#define XOUT_L 0x81
#define YOUT_H 0x82
#define YOUT_L 0x83
#define ZOUT_H 0x84
#define ZOUT_L 0x85
#define CTRL_REGA 0x8c
#define CTRL_REGC 0x0a
#define CTRL_REGB 0x0b
//#define spi_master 0x20
//#define spi_master 0x20
//INCLUDE
// #byte PORTC=0b10010xxx
//#byte TRISC=ob11111111
#byte TRISC=0b10010xxx
//TRISC0=1
//TRISC1=0
//TRISC2=0
//TRISC3=1
//TRISc4=0
#byte SSPSTAT=0b1100000x
#byte SSPCON1=0b00110001
#byte TXSTA=0b1011-010
#byte RCSTA=0b1011-11x
#byte SPBRG=0b00001001
//TRISB6=1
//TRISB7=1

//void enableinterrupts(void)

void main()
{
unsigned int a, b, XOUT, YOUT, ZOUT;
unsigned int spi_write, spi_read;
//setup_SSP(SPI_MASTER ,SPI_SLAVE )

setup_spi(spi_master, spi_slave)
//setupspi_master(0x20)
//setupspi_slave(0x24)
void spi_io(void);
{

CS=0 ; // chip slect low to write to registers
// a=0x8b
spi_write(0x0b); // intiates write to control regb
spi_write(0x86); // write operational mode byte to
control regb
// spi_write(0x0b && 0x86)
CS=1;
delay_us(130000);
CS=0;
spi_read(0x8b);
a=spi_read(0x86); // intiates the read from control reg b
CS=1;
delay_us(130000);
CS=0;
// b=0x8a
spi_write(0x0a); // intiates write to control regc
spi_write(0x00); // write operational mode byte to
control regc
// spi_write(0x0a && 0x00)
CS=1;
delay_us(130000);
CS=0;
spi_read(0x8a);
b=spi_read(0x00); //intiates the read from control reg c
CS=1;
delay_us(130000); //chip select high before the next data
request
CS=0;

//spi_write(0x06 && 0x14)
spi_write(FF_int_r);
spi_write(0x14);
delay_us(130000);
// spi_write(0x07 && 0x14)
spi_write(FF_delay_r);
spi_write(0x14);
delay_us(130000);
// spi_write(0x08 && 0x4d)
spi_write(MOT_int_r);
spi_write(0x4d);
delay_us(130000);
// spi_write(0x09 && 0x14)
spi_write(MOT_delay_r);
spi_write(0x14);
delay_us(130000);
// Axis conversion command
CS=0
XOUT=spi_read(0x80); // read
first 8 bits
SCLK=0;
delay_us(200);
XOUT=XOUT_H<<8; // shift
the first 8 bits to the left
XOUT!=spi_read(0x80); // read the
second 8 bits
XOUT= spi_read(0x80)>>4 // right
shift by 4 bits to go from 16 to 12 bits
CS=1
delay_ms(130000)
CS=0
YOUT=spi_read(0x82); // read
first 8 bits
SCLK=0;
delay_us(200);
YOUT=XOUT_H<<8; // shift
the first 8 bits to the left
YOUT!=spi_read(0x80); // read the
second 8 bits
YOUT= spi_read(0x80)>>4 // right
shift by 4 bits to go from 16 to 12 bits
CS=1
delay_ms(130000)
CS=0
ZOUT=spi_read(0x84); // read
first 8 bits
SCLK=0;
delay_us(200);
ZOUT=XOUT_H<<8; // shift
the first 8 bits to the left
ZOUT!=spi_read(0x80); // read the
second 8 bits
ZOUT= spi_read(0x80)>>4 // right
shift by 4 bits to go from 16 to 12 bits
CS=1
delay_ms(130000)
CS=0
/*spi_write(0x80);
SCLK=0;
delay_us(200);
XOUT_H=spi_read(0x80);
XOUT_L=spi_read(0x81);
CS=1;
delay_us(130000);

CS=0;
spi_write(0x82);
SCLK=0;
delay_us(200);
YOUT_H=spi_read(0x82);
YOUT_L=spi_read(0x83);
CS=1;
delay_us(130000);

CS=0;
spi_write(0x84);
SCLK=0;
delay_us(200);
ZOUT_H=spi_read(0x84);
ZOUT_L=spi_read(0x85)
CS=1;
delay_us(130000);*/

}
}

[code]

The data sheet of accelerometer is given below plz refer it if any
doubt.

http://www.kionix.com/accelerometers/accelerometer-KXP84.html



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