Texas Instruments MSP430 User Manual

285
// function to send I2C address with R/W bit
unsigned char i2c_usi_mst_send_address(unsigned char addr, unsigned char r_w)
{
addr <<= 1;
if(r_w)
{
addr |= 0x01;
}
return(i2c_usi_mst_send_byte(addr));
}
// USI I2C ISR function
#pragma vector=USI_VECTOR
__interrupt void USI_ISR (void)
{
if(USICTL1 & USISTTIFG)
{
// do something if necessary
// clear flag
USICTL1 &= ~USISTTIFG;
}
if(USICTL1 & USIIFG)
{
// USI counter interrupt flag
usi_cnt_flag = TRUE;
// clear flag
USICTL1 &= ~USIIFG;
}
//__bic_SR_register_on_exit(LPM0_bits);
}
PCF8574.h
#include "I2C.h"
#define PCF8574_address 0x20
unsigned char PCF8574_read(void);
void PCF8574_write(unsigned char data_byte);
PCF8574.c
#include "PCF8574.h"
unsigned char PCF8574_read(void)
{
unsigned char port_byte = 0x00;
i2c_usi_mst_gen_start();
i2c_usi_mst_send_address(PCF8574_address, rd);

Texas Instruments MSP430 Specifications

General

Brand	Texas Instruments
Model	MSP430
Category	Microcontrollers
Language	English