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hedin |
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#include <pic18.h>
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#include "MyI2C.h"
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#include "delay.h"
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#define LED RB3
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/****************************************************************************
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* Function:InitI2C *
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* Purpose: Initialize 100 kHz I2C communication *
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****************************************************************************/
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void InitI2C(void)
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{
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SSPADD = 0x0A; // 100 kHz I2C bus
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SSPCON1 = 0x28; // Enable I2C bus
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StopI2C();
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}
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/****************************************************************************
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* Function:StopI2C *
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* Purpose: End communication with I2C slave *
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* Send stop signal on I2C bus *
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* Input: Nothing *
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* Output: Nothing *
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****************************************************************************/
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void StopI2C(void)
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{
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SSPIF = 0; // Clear interrupt flag
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PEN = 1; // Send Stop condition
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while (SSPIF == 0); // Wait until stop condition complete
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}
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/****************************************************************************
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* Function:WaitForWrite EEProm *
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* Purpose: Wait for read write acces in EEProm *
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* Send start signal on I2C bus *
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* Send <I2CADD> on I2C bus *
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* Receive acknowledge from I2C slave *
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* Input: char I2CADD: Address of I2C slave to start communication with *
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* RWStruct *IOStruct2 ptr for data struct with Progress flag *
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* Output: 0: No communication started (missing acknowledge) *
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* 1: Communication started (acknowledge) *
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****************************************************************************/
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char WaitForWrite(char I2CADD, char *Progress)
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{
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int BreakCount = 5000;
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do{
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SSPIF = 0; // Clear interrupt flag
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RSEN = 1; // Initiate start condition
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while (SSPIF == 0)
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LED = LED^1; // Wait until Start condition complete
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SSPIF = 0; // Clear interrupt flag
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SSPBUF = I2CADD; // Send address of slave device
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while (SSPIF == 0)
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LED = LED^1; // Wait until address has been sent
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if(BreakCount-- == 0){
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LED = 0;
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*Progress = 0;
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return 0; // Return 0 if device didn't acknowledge
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}
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}while(ACKSTAT == 1);
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LED = 0;
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*Progress = 0;
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return 1; // Return 1 if device acknowledged
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}
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/****************************************************************************
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* Function:StartI2C *
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* Purpose: Initiate communication with I2C slave *
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* Send start signal on I2C bus *
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* Send <I2CADD> on I2C bus *
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* Receive acknowledge from I2C slave *
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* Input: char I2CADD: Address of I2C slave to start communication with *
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* Output: 0: No communication started (missing acknowledge) *
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* 1: Communication started (acknowledge) *
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****************************************************************************/
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char StartI2C(char I2CADD)
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{
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SSPIF = 0; // Clear interrupt flag
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RSEN = 1; // Initiate start condition
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while (SSPIF == 0)
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LED = LED^1; // Wait until Start condition complete
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SSPIF = 0; // Clear interrupt flag
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SSPBUF = I2CADD; // Send address of slave device
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while (SSPIF == 0)
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LED = LED^1; // Wait until address has been sent
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LED = 0;
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if (ACKSTAT == 0)
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return 1; // Return 1 if device acknowledged
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else
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return 0; // Return 0 if device didn't acknowledge
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}
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/****************************************************************************
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* Function:ReStartI2C *
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* Purpose: Initiate communication with I2C slave *
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* Send start signal on I2C bus *
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* Send <I2CADD> on I2C bus *
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* Receive acknowledge from I2C slave *
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* Input: char I2CADD: Address of I2C slave to start communication with *
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* Output: 0: No communication started (missing acknowledge) *
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* 1: Communication started (acknowledge) *
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****************************************************************************/
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char ReStartI2C(char I2CADD)
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{
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SSPIF = 0; // Clear interrupt flag
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RSEN = 1; // Initiate start condition
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while (SSPIF == 0)
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LED = LED^1; // Wait until Start condition complete
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SSPIF = 0; // Clear interrupt flag
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SSPBUF = I2CADD; // Send address of slave device
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while (SSPIF == 0)
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LED = LED^1; // Wait until address has been sent
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LED = 0;
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if (ACKSTAT == 0)
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return 1; // Return 1 if device acknowledged
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else
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return 0; // Return 0 if device didn't acknowledge
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}
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/****************************************************************************
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* Function:WriteI2CByte *
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* Purpose: Send 1 byte to I2C slave *
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* Input: 1 Data byte *
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* Output: 0: Communication did not succeed *
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* 1: Communication succeeded *
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****************************************************************************/
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char WriteI2CByte(char I2CByte)
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{
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SSPIF = 0;
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SSPBUF = I2CByte;
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// while(SSPIF == 0);
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Delay10us(1);
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if (ACKSTAT == 0)
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return 1; // Return 1 if device acknowledged
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else
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return 0; // Return 0 if device didn't acknowledge
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}
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/****************************************************************************
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* Function:ReadI2CByte *
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* Purpose: Send 1 byte to I2C slave *
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* Input: 1 Data byte *
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* Output: 0: Communication did not succeed *
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* 1: Communication succeeded *
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****************************************************************************/
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char ReadI2CByte(char LastRead)
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{
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char ReadChar=0;
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SSPIF = 0; // Clear interrupt flag
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RCEN = 1; // Initiate read sequence
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while (SSPIF == 0);
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ReadChar = SSPBUF; // Store byte in buffer
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SSPIF = 0;
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if(LastRead == 1){
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ACKDT = 1; // indicate we're done by no ack
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}else{
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ACKDT = 0; // else acknowledge the byte
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}
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ACKEN = 1; // Start acknowledge sequence
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return ReadChar;
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}
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/****************************************************************************
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* Function:WriteI2C *
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* Purpose: Send <I2CBYTES> bytes to I2C slave *
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* Input: char I2CADD: Address of I2C slave to start communication with *
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* char I2CBYTES: Number of bytes to send *
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* char*I2CBUFFER: Buffer containing data to send *
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* Output: 0: Communication did not succeed *
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* 1: Communication succeeded *
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****************************************************************************/
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char WriteI2C(RWStruct *IOStruct) //char DevAddr, char NoBytes, char *WriteBuffer);
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{
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char Count = 0;
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char Res = 1;
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if(IOStruct->WrInProgress == 1){
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Res = WaitForWrite(IOStruct->DevAddr & 0xfe, &IOStruct->WrInProgress);
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}else{
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Res = StartI2C(IOStruct->DevAddr & 0xfe);
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}
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if(Res == 1){
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if(!WriteI2CByte((char) IOStruct->RWAddress / 0x100))
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Res = 0;
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else if(!WriteI2CByte((char) IOStruct->RWAddress % 0x100))
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Res = 0;
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else{
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for(Count = 0; Count < IOStruct->NoBytes; Count++){
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if(WriteI2CByte(IOStruct->IOBuffer[Count]) == 0){
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Res = 0;
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break;
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}
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}
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}
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}else{
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Res = 0;
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}
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StopI2C();
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IOStruct->WrInProgress = 1;
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return Res;
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}
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/****************************************************************************
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* Function:ReadI2C *
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* Purpose: Reads <I2CBYTES> bytes to I2C slave *
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* Input: char I2CADD: Address of I2C slave to start communication with *
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* char I2CBYTES: Number of bytes to send *
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* char*I2CBUFFER: Buffer containing data to send *
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* Output: 0: Communication did not succeed *
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* 1: Communication succeeded *
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****************************************************************************/
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char ReadI2C(RWStruct *IOStruct) //char DevAddr, char NoBytes, char *ReadBuffer);
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{
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char Count = 0;
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char Ptr = 0;
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char Res = 1;
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if(IOStruct->WrInProgress == 1){
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Res = WaitForWrite(IOStruct->DevAddr & 0xfe, &IOStruct->WrInProgress);
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}else{
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Res = StartI2C( IOStruct->DevAddr & 0xfe);
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}
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if(Res == 1){
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if(!WriteI2CByte((char) IOStruct->RWAddress / 0x100))
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Res = 0;
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else if(!WriteI2CByte((char) IOStruct->RWAddress % 0x100))
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Res = 0;
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else if(!ReStartI2C(IOStruct->DevAddr | 0x1))
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Res = 0;
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else {
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Count = IOStruct->NoBytes - 1;
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for(Ptr = 0; Ptr < Count; Ptr++){
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IOStruct->IOBuffer[Ptr] = ReadI2CByte(0);
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}
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IOStruct->IOBuffer[Ptr] = ReadI2CByte(1);
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}
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StopI2C();
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}
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return Res;
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}
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