📄 main.c
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/*********************************************************************/
/* Project Name: IIC_Master.mcp */
/* Source fle name: IIC_Master.c */
/*********************************************************************/
/* Copyright (C) 2007 Freescale Semiconductor, Inc. */
/* All Rights Reserved */
/*********************************************************************/
/*********************************************************************/
/* Hands on training for QE128 MCU's */
/* Module: IIC */
/* The firmware was developed and tested on CodeWarrior 6.0 version */
/* */
/* Description: Once the IIC module is configured, the master will */
/* send the slave a counter value. The counter value will be display */
/* in both boards (Master and Slave) */
/*********************************************************************/
/* */
/* Date: 12/03/2007 */
/* Ulises Corrales Salgado */
/* Application Engineer */
/* RTAC Americas */
/*********************************************************************/
#include <hidef.h> /* for EnableInterrupts macro */
#include "derivative.h" /* include peripheral declarations */
typedef unsigned char UINT8;
typedef unsigned int UINT16;
UINT8 last_byte = 0;
UINT8 counter = 0;
UINT8 last_byte_to_rec = 0;
UINT8 add_cycle = 0;
UINT8 count = 0;
UINT8 rec_count = 0;
UINT8 num_to_rec = 0;
UINT8 bytes_to_trans = 0;
UINT8 IIC_Data[9];
UINT8 IIC_Rec_Data[9];
UINT8 IIC_TX_Data[9];
/*********************************************************************/
/* Function declarations */
/*********************************************************************/
void MCU_Init(void) {
SOPT1 = 0x23; /* Watchdog disable */
SCGC1 = 0x08; /* Bus Clock to the IIC2 module is enabled */
}
void GPIO_Init(void) {
PTHPE = 0xC0; /* Enable Pull ups on PTH7 and PTH6 pins */
PTCDD = (UINT8) (PTCD | 0x3F); /* Configure PTC0-PTC6 as outputs */
PTEDD = (UINT8) (PTED | 0xC0); /* Configure PTE6 and PTE7 pins as outputs */
PTCD = 0x3F; /* Put 1's in port C in order to turn off the LEDs */
PTED = 0xC0; /* Put 1's in port E port in order to turn off the LEDs */
}
void IIC_configuration (void) {
IIC2A = 0xAA;
IIC2F = 0x09; /* Multiply factor of 1. SCL divider of 32 */
IIC2C1 = 0xC0; /* Enable IIC module and interrupts */
}
void Delay (UINT16 c) { /* This delay function is used to spend some time */
/* before sending the next byte */
UINT16 i = 0;
for (i; i<=c; i++) {
}
}
/*********************************************************************/
/* Function used as Master */
/*********************************************************************/
void Master_Read_and_Store(void) {
if (rec_count == num_to_rec) {
last_byte_to_rec = 2;
}
IIC_Rec_Data[rec_count] = IIC2D;
rec_count++;
}
void Master_Transmit(UINT8 a, UINT8 b) { /* This function transmits commands to a Slave */
last_byte = 0; /* Initialize variables to 0 */
count = 0;
bytes_to_trans = a; /* Initialize Data Array with Commands */
num_to_rec = b;
IIC2C1_TX = 1; /* Set TX bit for Address cycle */
IIC2C1_MST = 1; /* Set Master Bit to generate a Start */
IIC2D = 0xAA; /* Send Address data LSB is R or W for Slave */
}
void Master_Receive() {
rec_count = 0; /* Initialize variables to 0 */
last_byte_to_rec = 0;
last_byte = 0;
count = 0;
num_to_rec = 0;
IIC2C1_TXAK =0;
IIC2C1_TX = 1; /* Set TX bit for Address cycle */
IIC2C1_MST = 1; /* Set Master Bit to generate a Start */
add_cycle = 1; /* This variable sets up a master rec in the ISR */
IIC2D = 0xAB; /* Send Address data LSB is R or W for Slave */
}
/*********************************************************************/
/* Function used as Slave */
/*********************************************************************/
void Slave_Read_and_Store(void) {
if (rec_count == num_to_rec) {
last_byte_to_rec = 2;
}
IIC_Rec_Data[rec_count] = IIC2D;
rec_count++;
if (rec_count == num_to_rec) {
rec_count = 0;
}
}
void SRW(void) {
if (IIC2S_SRW) { /* Check for Slave Rec or transmit */
IIC2C1_TX = 1; /* Set Tx bit to begin a Transmit */
IIC2D = IIC_TX_Data[count];
count++;
}
else {
IIC2C1_TX = 0; /* An acknowledge signal will be sent out to the bus */
/* after receiveing one data byte */
IIC2D; /* Dummy read */
}
}
/*********************************************************************/
/* Main Function */
/*********************************************************************/
void main(void) {
UINT8 temp = 0;
MCU_Init(); /* Function that initializes the MCU */
GPIO_Init(); /* Function that initializes the Ports of the MCU */
IIC_configuration(); /* Function that initializes the IIC module */
EnableInterrupts; /* enable interrupts */
num_to_rec = 1;
for(;;) {
_Wait;
temp = rec_count;
PTED = (UINT8) (temp & 0xC0); /* Move the received value to port E */
PTCD = (UINT8) (temp & 0x3F); /* Move the received value to port C */
}
}
/*********************************************************************/
/* Interrupt Service Routine */
/*********************************************************************/
interrupt VectorNumber_Viicx void IIC_ISR(void) {
IIC2S_IICIF = 1; /* Clear Interrupt Flag */
if (IIC2C1_MST) /* Master or Slave? */
{
/***************************** Master **********************************/
if (IIC2C1_TX) /* Transmit or Receive? */
{
/********************* Transmit ***********************/
if (last_byte) { /* Is the Last Byte? */
IIC2C1_MST = 0; /* Generate a Stop */
}
else if (last_byte != 1) {
if (IIC2S_RXAK) { /* Check for ACK */
IIC2C1_MST = 0; /* No ACk Generate a Stop */
}
else if (!IIC2S_RXAK) {
if (add_cycle) { /* Is Address Cycle finished? Master done addressing Slave? */
add_cycle = 0; /* Clear Add cycle */
IIC2C1_TX = 0; /* Switch to RX mode */
IIC2D; /* Dummy read from Data Register */
}
else if (add_cycle != 1) {
IIC2D = counter; /* Transmit Data */
count++;
if (count == bytes_to_trans) {
last_byte = 1;
}
}
}
}
}
else {
/********************* Receive *************************/
if (last_byte_to_rec == 1) {
IIC2C1_MST = 0; /* Last byte to be read? */
Master_Read_and_Store();
}
else if (last_byte_to_rec == 2) { /* Second to last byte to be read? */
last_byte_to_rec = 1;
IIC2C1_TXAK = 1; /* This sets up a NACK */
Master_Read_and_Store();
}
else {
Master_Read_and_Store();
}
}
}
else {
/***************************** Slave **********************************/
if (IIC2S_ARBL) {
IIC2S_ARBL = 1;
if (IIC2S_IAAS) { /* Check For Address Match */
count = 0;
SRW();
}
}
else {
if (IIC2S_IAAS) { /* Arbitration not Lost */
count = 0;
SRW();
}
else {
if (IIC2C1_TX) { /* Check for rec ACK */
if (!IIC2S_RXAK) { /* ACK Recieved */
IIC2D = IIC_TX_Data[count];
count++;
}
else {
IIC2C1_TX = 0;
IIC2D;
}
}
else {
Slave_Read_and_Store();
}
}
}
}
}
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