MMA8451 accelerometer

with all those comments, I'm just eager to help you

with all those comments, I'm just eager to help you

i am sorry not to write the comments.
will try to add comments and upload. thanks.

till then kindly go through the code if possible.
the _nop_() are added for small delay generation.

#include "twi.h"

sbit SDA = P1^7;
sbit SCL = P1^5;

void I2CInit(void)
{
        SDA = 1;
        SCL = 1;
}


void I2CStart(void)
{
        SDA = 1;    //Start condition
        SCL = 1;
        SDA = 0;
        SCL = 0;
}


void I2CRestart(void)
{
        SDA = 1;     //Transmit restart condition. I dont kno this is correct restart condition or not
        SCL = 1;
        SDA = 0;
        SCL = 0;
}


void I2CStop(void)
{
        SDA = 0;    //stop condition at the end of transmission
        SCL = 1;
        SDA = 1;
}


void I2CAck(void)
{
        SDA = 0;    //transmit ack
        SCL = 1;
        SCL = 0;
}


void I2CNak(void)
{
        SDA = 1;    //transmitt nack
        SCL = 1;
        SCL = 0;
}


unsigned char I2CSend(unsigned char Data)
{
        unsigned char i, ack_bit;

        for(i=0;i<8;i++)      //send data out on sda line with msb first
        {
                SCL = 0;
                if ((Data & 0x80) == 0)
                        SDA = 0;
                else
                        SDA = 1;

                SCL = 1;
                Data<<=1;
        }
        SCL = 0;
        SDA = 1;              //configure as input pin. doubtful
        SCL = 1;
        ack_bit = SDA;        //read ack bit
        SCL = 0;
        return !ack_bit;     //i m doubtful about this
}


unsigned char I2CRead(void)
{
        unsigned char i, Data=0;

        for(i=0;i<8;i++)
        {
                SDA = 1;         //read the 8bit data
                SCL = 0;
                SCL = 1;

                if(SDA)
                        Data |=1;
                if(i<7)
                        Data<<=1;
        }
        SCL = 0;
        SDA = 1;
        return Data;
}

all the functions are named. so thought that comments may not be required.

MMA8451 is 3.3Volts. Are you connecting it directly to your uC and if so, what voltage is it running at?

MMA8451 is running at 3.3V and uC is running at 5V

The mma8451 interface was successful. i can now read X-axis & Y-axis data continuously.

I want to convert the values into angular positions expressed in degrees. how do i do that?
the mma8451 is configured for 2g.

also, depending upon 2g, 4g, 8g, what is the effect on the sensitivity (i mean the number of counts generated)?