CCS/MSP430G2210: function calling error

Tool/software: Code Composer Studio

I have written a simple code for softi2c. Initialise, start and send byte are working fine. Untill i pack the send byte code into a function.
If the send byte function is not made separately but rather pasted in main(), it works and A0 is transmitted successfully.
But soon as i pack it in a function, i get following error:

error #148: declaration is incompatible with "void i2c_send_byte()"

CCSv5

#include "msp430g2210.h"

#define SDA BIT2
#define SCL BIT5

void init_i2c();
void i2c_start();
void i2c_send_byte(A0);

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer

init_i2c();
i2c_start();
i2c_send_byte(0xA0);  // send A0

while(1);     // wait forever
}

void init_i2c()
{
  P1DIR |= (SDA + SCL); // Set P2.2 and P2.3 to output direction
}

void i2c_start()
{
  P1OUT |= (SDA + SCL);
  __delay_cycles(5);
  P1OUT &= ~SDA;      // SDA=1->0 while SCL=1
}

void i2c_send_byte(unsigned char byte)
{
      unsigned char i,tmp;        // Variable to be used in for loop

    for(i=0;i<8;i++)        // Repeat for every bit
    {
        P1OUT &= ~SCL;
        __delay_cycles(1);
        tmp=(((byte<<i)&0x80)?(P1OUT|=SDA):(P1OUT&=~SDA));  // Place data bit value on SDA pin depending on 0 or 1 bit
        __delay_cycles(1);
        P1OUT |= SCL;      // Toggle SCL pin so that slave can latch data bit
        __delay_cycles(1);
  }

    // Get ACK from slave
    P1OUT &= ~SCL;
    P1OUT |= SDA;
    __delay_cycles(1);
  P1OUT |= SCL;
  __delay_cycles(1);

}