MC9S12C32 to drive MMA7455L freescale accelerometer

[ersancan]

Hello. im trying to drive mma7455l accelerometer with a csm12c32 dev. board( has mc9s12c32 micrprocessor on it). i couldnt manage to use spi module somehow. and now im trying to use gpio pins to communicate with accelerometer. i have another problem now. i cannot write a r/w register of accelerometer but i can read register values. here is my source code to communicate through gpio pins:

#include <hidef.h> /* common defines and macros */
#include <mc9s12c32.h> /* derivative information */
#pragma LINK_INFO DERIVATIVE "mc9s12c32"

#define CS_HIGH ( PTT = PTT | 0x01) //|0000|0001|
#define CS_LOW ( PTT = PTT & 0xFE) //|1111|1110|
#define SCL_HIGH ( PTT = PTT | 0x02) //|0000|0010|
#define SCL_LOW ( PTT = PTT & 0xFD) //|1111|1101|
#define SDO_HIGH ( PTT = PTT | 0x04) //|0000|0100|
#define SDO_LOW ( PTT = PTT & 0xFB) //|1111|1011|

unsigned char val=0;

void main(void);
void initSPI(void);
void Delay10TCY();
void Delay10KTCYx(int i);
unsigned char ReadSPI(unsigned char address);
void WriteSPI(unsigned char address, unsigned char data);
unsigned char SPI_RByte(void);
void SPI_WByte(unsigned char data);


void main(void) {
EnableInterrupts;

DDRA = 0x01;
DDRB = 0x10;
PORTA = 0x01;
PORTB = 0x10;
initSPI();

for(;{
val=0; // reset value
//PORTA = 0x01; // turn LED OFF

//Set up MMA7455L operation mode by writing to hex addr 16, hex value 05 (2g, 4 wires)
WriteSPI(0x16,0x05);
Delay10KTCYx(100);
val = ReadSPI(0x16);// read value back from register and if expected value turn ON the LED

if(val==0x05){
PORTA = 0x00;
}// turn LED ON
/*
else{
PORTA = 0x01;
}// turn LED OFF
*/

Delay10KTCYx(100);

if(PORTB == 0x00)
PORTB = 0x10;
else
PORTB = 0x00;
}
}


void initSPI(void){
DDRT = 0x07; //|0000|0111|
CS_HIGH;
SDO_LOW;
SCL_LOW;
}

void Delay10TCY(){
int x;
for(x=0;x<255;x++){}
}

void Delay10KTCYx(int i){
int x;
for(x=0;x<i;x++){
Delay10TCY();
}
}

void SPI_WByte(unsigned char data){
char x;
for(x=0;x<8;x++){ //Loop 8 bits
SCL_LOW; //Clock Low
Delay10TCY();
SDO_HIGH;
if((data & 0x80) == 0)//Clear entire byte except bit 7 and check if byte is greater than 0
SDO_LOW; //Set the Data Out to HIGH
Delay10TCY(); //Delay 5uS
SCL_HIGH; //Clock High
Delay10TCY(); //Delay 5uS
data <<= 1; //Shift data bit out to the right
}
Delay10TCY(); //Delay 5uS
}

unsigned char SPI_RByte(void){
char x,data;
for(x=0;x<8;x++){ //Loop 8 bits
SCL_LOW; //Clock Low
Delay10TCY(); //5uS delay
data <<= 1; //Shift 1 bit to the left
data &= 0xFE; //Clear BIT 0 from byte without touching the rest
if( (PTT & 0x08) > 0) //if the Serial Data In is HIGH do below if not then leave it 0
data |= 1; //OR in a 1 into out byte
SCL_HIGH; //Clock High
Delay10TCY(); //5uS delay
}
Delay10TCY(); //Delay 5uS
return data; //return our data
}

void WriteSPI(unsigned char address, unsigned char data){
SCL_HIGH; //Clock High
CS_LOW; //Chip Select Low
address = ( ( ( address << 1 ) & 0x7E ) | 0x81 );
SPI_WByte(address); //Write our address
SPI_WByte(data); //Write our data
CS_HIGH; //Chip Select High
}

unsigned char ReadSPI(unsigned char address){
unsigned char tmp;
SCL_HIGH; //Clock High
CS_LOW; //Chip Select Low
address=( ( address << 1 ) & 0x7E );//Send read command together with reg address
SPI_WByte(address); //Write our address to read from
tmp = SPI_RByte(); //Get the byte from the device
CS_HIGH; //Chip Select High
return tmp; //Return tmp
}

by the way, i forgot to mention how i am sure about i can read registers. there is a register that keeps i2c address of the accelerometer. register address is 0x0D and value is 0x1D. i switch on a led if i read 1D value from 0D address.

is there any thing wrong with src? i need a help very badly.

ps: if anyone has a tested & working source code using spi module to share, that would be great too.

Have a good day