#include<pic.h>
#define uchar unsigned char
#define uint unsigned int
__CONFIG(UNPROTECT & BOREN & MCLRDIS & PWRTEN & WDTDIS & INTOSCIO);
#define SDA RC0
#define SCL RC1
#define SDA_DIR TRISC0
#define SCL_DIR TRISC1
#define SDA_HIGH() SDA_DIR=1
#define SDA_LOW() SDA_DIR=0
#define SCL_HIGH() SCL_DIR=1
#define SCL_LOW() SCL_DIR=0
#define I2C_TM_BUS_FREE 5 // min. 600ns
#define I2C_TM_START_SU 5 // min. 100ns
#define I2C_TM_START_HD 4 // min. 100ns
#define I2C_TM_SCL_LOW 5 // min. 1300ns
#define I2C_TM_SCL_HIGH 4 // min. 600ns
#define I2C_TM_DATA_SU 1 // min. 100ns
#define I2C_TM_DATA_HD 0 // min. 0ns
#define I2C_TM_SCL_TO_DATA 4 // max. 300ns /* SCL low to data valid */
#define I2C_TM_STOP_SU 4 // min. 100ns
#define I2C_TM_SCL_TMO 10 // max. 1000ns /* clock time out */
#define I2C_ERROR (-1)
#define FALSE 0
#define TRUE !FALSE
#ifndef XTAL_FREQ
#define XTAL_FREQ 4MHZ /* Crystal frequency in MHz */
#endif
#define MHZ *1000L /* number of kHz in a MHz */
#define KHZ *1 /* number of kHz in a kHz */
#define LEDoff PORTA=0b00000000;TRISA=0b00001111
#define LED0on PORTA=0b00010000;TRISA=0b11001111
#define LED1on PORTA=0b00100000;TRISA=0b11001111
#define BUTTON RA3
void DelayUs(uchar x);
void DelayMs(uchar cnt);
void start();
void stop();
uchar ReadAck();
void SendAck(uchar status);
uchar i2c_WaitForSCL();
uchar SendByte(uchar byte);
uchar ReadByte();
uchar ReadFrom(uchar address);
void FlashLED0();
void FlashLED1();
uchar tem1,tem2;
float Temperature;
uint temper;
void main()
{
TRISC=0Xff; //PORTC Input SCL=RC1,SDA=RC0
PORTC=0X00;
while(1)
{
if(BUTTON==0)
{
DelayMs(10);
if(BUTTON==0)
{
while(!BUTTON);
start();
SendByte(0b10010010);
ReadAck();
SendByte(0x00);
ReadAck();
stop();
start();
SendByte(0b10010011);
ReadAck();
temper=ReadByte();
//SendAck(TRUE);
//tem2=ReadByte();
//SendAck(FALSE);
stop();
DelayMs(250);
if(temper==0b00000000) {LED1on;} //!!!!here is the problem!!!
//uchar a;
//a=tem1*16+tem2/16;
//Temperature=(tem1*16+tem2/16)*0.0625;
//temper=(int)Temperature;
//LED0on;
}
}
}
}
void start()
{
SCL_LOW(); /* ensure clock is low */
SDA_HIGH(); /* ensure data is high */
DelayUs(I2C_TM_DATA_SU);
SCL_DIR = 1; /* clock pulse high */
DelayUs(I2C_TM_SCL_HIGH);
SDA_LOW(); /* the high->low transition */
DelayUs(I2C_TM_START_HD);
return;
}
void stop()
{
SDA_LOW(); /* ensure data is low first */
SCL_HIGH();
DelayUs(I2C_TM_DATA_SU);
SCL_DIR =1; /* float clock high */
DelayUs(I2C_TM_STOP_SU);
SDA_HIGH(); /* the low->high data transistion */
DelayUs(I2C_TM_BUS_FREE); /* bus free time before next start */
SDA_DIR = 1; /* float data high */
return;
}
uchar ReadAck()
{
uchar ack;
SCL_LOW(); /* make clock is low */
SDA_DIR = 1; /* disable data line - listen for ack */
DelayUs(I2C_TM_SCL_TO_DATA); /* SCL low to data out valid */
SCL_DIR = 1; /* float clock high */
DelayUs(I2C_TM_DATA_SU);
ack = SDA; /* read the acknowledge */
return ack;
}
void SendAck(uchar status)
{
SCL_LOW();
if ( status & 0x01) {
SDA_LOW(); /* drive line low -> more to come */
}
else {
SDA_HIGH();
}
DelayUs(I2C_TM_DATA_SU);
SCL_DIR = 1; /* float clock high */
DelayUs(I2C_TM_SCL_HIGH);
return;
}
uchar i2c_WaitForSCL()
{
/* SCL_DIR should be input here */
if(!SCL)
{
DelayUs(I2C_TM_SCL_TMO);
/* if the clock is still low -> bus error */
if(!SCL)
return TRUE;
}
return FALSE;
}
uchar SendByte(uchar byte)
{
uchar i;
for (i=0;i<8;i++)
{
SCL_LOW(); /* drive clock low */
/* data hold time = 0, send data now */
SDA_DIR = ((byte<<i)&0x80); /* bit to send */
if ((byte<<i)&0x80) {
SDA_HIGH();
}
else {
SDA_LOW();
}
DelayUs(I2C_TM_DATA_SU);
SCL_DIR = 1; /* float clock high */
DelayUs(I2C_TM_SCL_HIGH); /* clock high time */
}
return FALSE;
}
uchar ReadByte()
{
unsigned char i;
unsigned char byte = 0;
for(i=0; i<8; i++)
{
SCL_LOW(); /* drive clock low */
DelayUs(I2C_TM_SCL_LOW); /* min clock low period */
SDA_DIR = 1; /* release data line */
SCL_DIR = 1; /* float clock high */
DelayUs(I2C_TM_SCL_HIGH);
byte = byte << 1; /* read the next bit */
byte |= SDA;
}
return byte;
}
}
void DelayUs(uchar x)
{ uchar _dcnt;
_dcnt = (x)/((12MHZ)/(XTAL_FREQ))|1;
while(--_dcnt != 0)
continue;
}
void DelayMs(uchar cnt)
{
uchar i;
do {
i = 4;
do {
DelayUs(250);
} while(--i);
} while(--cnt);
}
void FlashLED1()
{
LED1on;
DelayMs(200);
LEDoff;
DelayMs(200);
}
void FlashLED0()
{
LED0on;
DelayMs(200);
LEDoff;
DelayMs(200);
}
========================================================================================
Sorry for a so long Program first.
I'm a newer for microcontroll and just learn C for a short time. now i'm using a pic16f676 from Microchip and TMP112.
I have programmed the code and also get the data from an o-scope, but I don't know why I get nothing through the sentence
"temper=ReadByte(); ".
In fact ReadByte equals to 0.
But why from the o-scope, ReadByte()= ob00011000?
