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code:capdac [2009/05/19 23:36] – created laurencebcode:capdac [2009/05/19 23:42] (current) – laurenceb
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 +====== AD7746 demo code ======
 <code c > <code c >
 #include <stdio.h> #include <stdio.h>
- 
 #include <stdlib.h> #include <stdlib.h>
- 
 #include <avr/io.h> #include <avr/io.h>
- 
 #include <util/twi.h> //I2C registers #include <util/twi.h> //I2C registers
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 #include <util/delay_basic.h> //wait delay loop for page write #include <util/delay_basic.h> //wait delay loop for page write
  
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 #define SCL 50000 //100KHz clock #define SCL 50000 //100KHz clock
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 #define _AK_ (1<<TWINT)|(1<<TWEN)|(1<<TWEA) //for setting up I2C read with AK and NAK from master #define _AK_ (1<<TWINT)|(1<<TWEN)|(1<<TWEA) //for setting up I2C read with AK and NAK from master
- 
 #define _NAK_ (1<<TWINT)|(1<<TWEN) #define _NAK_ (1<<TWINT)|(1<<TWEN)
 #define F_CPU 20000000UL #define F_CPU 20000000UL
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 typedef unsigned char u08; typedef unsigned char u08;
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 typedef unsigned short u16; typedef unsigned short u16;
  
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 #define BAUDRATE (unsigned long)9600 #define BAUDRATE (unsigned long)9600
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 #define BAUDDIV  (u16)( ((float)F_CPU/(BAUDRATE*16UL)) -1 )//baud divider #define BAUDDIV  (u16)( ((float)F_CPU/(BAUDRATE*16UL)) -1 )//baud divider
 void init_i2c(void); void init_i2c(void);
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 void init_i2c() void init_i2c()
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 { {
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  TWBR=(u08)(((float)F_CPU/(2.0*(float)SCL))-8.0);//sets the correct clock rate defined as SCL  TWBR=(u08)(((float)F_CPU/(2.0*(float)SCL))-8.0);//sets the correct clock rate defined as SCL
- 
 } //we dont need to enable the hardware - its done in write } //we dont need to enable the hardware - its done in write
  
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 void i2cstart() void i2cstart()
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 { {
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  u16 timeout=1;  u16 timeout=1;
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  TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN); //send start  TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN); //send start
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  while (!(TWCR & (1<<TWINT)) && timeout)  while (!(TWCR & (1<<TWINT)) && timeout)
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  timeout++; //wait for a start to be transmitted  timeout++; //wait for a start to be transmitted
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  if(!timeout)  if(!timeout)
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  I2Cerr|=16; //timeout out waiting for start error  I2Cerr|=16; //timeout out waiting for start error
- 
  TWCR = (1<<TWEN ); //clear the start condition  TWCR = (1<<TWEN ); //clear the start condition
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  if (((TWSR & 0xF8) != TW_START)&&((TWSR & 0xF8) != TW_REP_START))  if (((TWSR & 0xF8) != TW_START)&&((TWSR & 0xF8) != TW_REP_START))
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  I2Cerr|=1; //error  I2Cerr|=1; //error
- 
 } }
  
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 void i2cstop() void i2cstop()
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 { {
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  u16 timeout=1;  u16 timeout=1;
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  TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);  TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
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  while (!(TWCR & (1<<TWSTO)) && timeout)//wait for stop to be sent  while (!(TWCR & (1<<TWSTO)) && timeout)//wait for stop to be sent
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  timeout++;  timeout++;
- 
  if(!timeout)  if(!timeout)
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  I2Cerr|=64; //timeout waiting for stop error  I2Cerr|=64; //timeout waiting for stop error
- 
 } }
  
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 void i2cwrite(u08 c) void i2cwrite(u08 c)
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 { {
- 
  u16 timeout=1;  u16 timeout=1;
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  TWDR = c; //load the data  TWDR = c; //load the data
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  TWCR = (1<<TWINT)|(1<<TWEN);  TWCR = (1<<TWINT)|(1<<TWEN);
- 
  while (!(TWCR & (1<<TWINT)) && timeout)//wait for it to be sent  while (!(TWCR & (1<<TWINT)) && timeout)//wait for it to be sent
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  timeout++;  timeout++;
- 
  if(!timeout)  if(!timeout)
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  I2Cerr|=32; //timeout out waiting for write complete error  I2Cerr|=32; //timeout out waiting for write complete error
- 
  if ( ((TWSR&0xF8)!=TW_MT_SLA_ACK)&&((TWSR&0xF8)!=TW_MR_SLA_ACK)&&((TWSR&0xF8)!=TW_MT_DATA_ACK) )  if ( ((TWSR&0xF8)!=TW_MT_SLA_ACK)&&((TWSR&0xF8)!=TW_MR_SLA_ACK)&&((TWSR&0xF8)!=TW_MT_DATA_ACK) )
- 
  I2Cerr|=2; //error  I2Cerr|=2; //error
- 
 } }
- 
    
- 
 u08 i2cread(u08 ak) u08 i2cread(u08 ak)
- 
 { {
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  u16 timeout=1;  u16 timeout=1;
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  TWCR=ak;  TWCR=ak;
- 
  while ((!(TWCR & (1<<TWINT))) && timeout)  while ((!(TWCR & (1<<TWINT))) && timeout)
- 
  timeout++; //wait for it to be recieved  timeout++; //wait for it to be recieved
- 
  if(!timeout)  if(!timeout)
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  I2Cerr|=8; //timeout out waiting for data response error  I2Cerr|=8; //timeout out waiting for data response error
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  if(((TWSR & 0xF8) !=TW_MR_DATA_ACK) && ((TWSR & 0xF8) !=TW_MR_DATA_NACK))  if(((TWSR & 0xF8) !=TW_MR_DATA_ACK) && ((TWSR & 0xF8) !=TW_MR_DATA_NACK))
- 
  I2Cerr|=4;  I2Cerr|=4;
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  return TWDR;  return TWDR;
- 
 } }
- 
- 
  
 //comms //comms
- 
- 
  
 int put_char(char c, FILE * stream) int put_char(char c, FILE * stream)
- 
 { {
- 
  while(!(UCSR0A & (1<<UDRE0))); //unbuffered tx comms  while(!(UCSR0A & (1<<UDRE0))); //unbuffered tx comms
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  UDR0 = c;  UDR0 = c;
- 
  return 0;  return 0;
- 
 } }
- 
- 
  
 int get_char(FILE * stream) int get_char(FILE * stream)
- 
 { {
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  while( !(UCSR0A & (1<<RXC0)) );  while( !(UCSR0A & (1<<RXC0)) );
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   return(UDR0);   return(UDR0);
- 
 } }
- 
- 
  
 //the main code //the main code
- 
- 
  
 int main() int main()
- 
 { {
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  //setup code  //setup code
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  UCSR0B = (1<<RXEN0)|(1<<TXEN0); //mega xx8 registers - enable tx and rx, with no interrupts  UCSR0B = (1<<RXEN0)|(1<<TXEN0); //mega xx8 registers - enable tx and rx, with no interrupts
- 
  UCSR0C = (1<<UPM01)|(1<<UPM00)|(1<<UCSZ01)|(1<<UCSZ00);//setup 8O1  UCSR0C = (1<<UPM01)|(1<<UPM00)|(1<<UCSZ01)|(1<<UCSZ00);//setup 8O1
- 
  UBRR0L = BAUDDIV;  UBRR0L = BAUDDIV;
- 
  UBRR0H = BAUDDIV>>8; //end of UART setup  UBRR0H = BAUDDIV>>8; //end of UART setup
- 
  FILE mystdio = FDEV_SETUP_STREAM(put_char, get_char, _FDEV_SETUP_RW);  FILE mystdio = FDEV_SETUP_STREAM(put_char, get_char, _FDEV_SETUP_RW);
- 
  stdout=&mystdio;  stdout=&mystdio;
- 
  unsigned char command_humidity[]={0x90,0x07,0x81,0x81,0x23,0x01,0xFF};//the humi channel and the temp sensor  unsigned char command_humidity[]={0x90,0x07,0x81,0x81,0x23,0x01,0xFF};//the humi channel and the temp sensor
- 
  unsigned char command_level[]={0x90,0x07,0xC1,0x81,0x0B,0x01,0xFF};//the level sensor channel  unsigned char command_level[]={0x90,0x07,0xC1,0x81,0x0B,0x01,0xFF};//the level sensor channel
- 
  init_i2c(); //initialise the I2C  init_i2c(); //initialise the I2C
- 
  unsigned char n,m,l;  unsigned char n,m,l;
- 
  unsigned long int b;  unsigned long int b;
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  float humidity,temperature,level;  float humidity,temperature,level;
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  printf("Hello world\n\r");  printf("Hello world\n\r");
- 
  while(1)  while(1)
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  {  {
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  for(m=0;m<100;m++)  for(m=0;m<100;m++)
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  {  {
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  i2cstart();  i2cstart();
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  i2cwrite(0xBF); //reset the AD7746  i2cwrite(0xBF); //reset the AD7746
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  i2cstop();  i2cstop();
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  I2Cerr=0;  I2Cerr=0;
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  i2cstart();  i2cstart();
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  for(n=0;command_humidity[n]!=0xFF;n++)  for(n=0;command_humidity[n]!=0xFF;n++)
- 
  {  {
- 
  i2cwrite(command_humidity[n]);  i2cwrite(command_humidity[n]);
- 
  }  }
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  i2cwrite(255); //the capdac setting for humidity  i2cwrite(255); //the capdac setting for humidity
- 
  do{ //wait for the conversion  do{ //wait for the conversion
- i2cstop(); + i2cstop();
  i2cstart();  i2cstart();
  i2cwrite(0x90);  i2cwrite(0x90);
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  }while(i2cread(_NAK_)&0x04);   }while(i2cread(_NAK_)&0x04);
  i2cstop();  i2cstop();
- 
  i2cstart();  i2cstart();
- 
  i2cwrite(0x90);  i2cwrite(0x90);
- 
  i2cwrite(0x01); //set to first register  i2cwrite(0x01); //set to first register
- 
  i2cstart(); //restart  i2cstart(); //restart
- 
  i2cwrite(0x91); //read from slave  i2cwrite(0x91); //read from slave
- 
  b=0;  b=0;
- 
  for(n=3;n;n--)  for(n=3;n;n--)
- 
  {  {
- 
  b|=((unsigned long int)i2cread(_AK_))<<(8*(n-1));  b|=((unsigned long int)i2cread(_AK_))<<(8*(n-1));
- 
  }  }
- 
  humidity+=((float)b)/1.67e8;  humidity+=((float)b)/1.67e8;
- 
  b=0;  b=0;
- 
  for(n=2;n;n--)  for(n=2;n;n--)
- 
  b|=((unsigned long int)i2cread(_AK_))<<(8*n);  b|=((unsigned long int)i2cread(_AK_))<<(8*n);
- 
  b|=(unsigned long int)i2cread(_NAK_);  b|=(unsigned long int)i2cread(_NAK_);
- 
  temperature+=((((float)b)/2048.0)-4096.0)/100.0;  temperature+=((((float)b)/2048.0)-4096.0)/100.0;
  i2cstop();  i2cstop();
- 
  i2cstart();  i2cstart();
- 
  i2cwrite(0xBF); //reset the AD7746  i2cwrite(0xBF); //reset the AD7746
- 
  i2cstop();  i2cstop();
- 
  i2cstart();  i2cstart();
- 
  for(n=0;command_level[n]!=0xFF;n++)  for(n=0;command_level[n]!=0xFF;n++)
- 
  i2cwrite(command_level[n]);   i2cwrite(command_level[n]);
- 
  i2cwrite(190); //the capdac setting  i2cwrite(190); //the capdac setting
  do{ //wait for the conversion  do{ //wait for the conversion
Line 313: Line 188:
  l=i2cread(_NAK_);  l=i2cread(_NAK_);
  }while(l&0x04);  }while(l&0x04);
- 
  i2cstop();  i2cstop();
- 
  i2cstart();  i2cstart();
- 
  i2cwrite(0x90);  i2cwrite(0x90);
- 
  i2cwrite(0x01); //set to first register  i2cwrite(0x01); //set to first register
- 
  i2cstart(); //restart  i2cstart(); //restart
- 
  i2cwrite(0x91); //read from slave  i2cwrite(0x91); //read from slave
- 
  b=0;  b=0;
- 
  for(n=2;n;n--)  for(n=2;n;n--)
- 
  b|=((unsigned long int)i2cread(_AK_))<<(8*n);  b|=((unsigned long int)i2cread(_AK_))<<(8*n);
- 
  b|=(unsigned long int)i2cread(_NAK_);  b|=(unsigned long int)i2cread(_NAK_);
- 
  level+=((float)b)/1.67e8;  level+=((float)b)/1.67e8;
- 
  i2cstop();  i2cstop();
- 
  }  }
  putchar(12);  putchar(12);
- 
  printf("Temperature=%f\n\r Humidity=%f\n\r Level=%f\r\n",(double)temperature,(double)humidity,(double)level);  printf("Temperature=%f\n\r Humidity=%f\n\r Level=%f\r\n",(double)temperature,(double)humidity,(double)level);
  printf("Status:%2X\n\r",l);  printf("Status:%2X\n\r",l);
- 
  temperature=0;  temperature=0;
- 
  humidity=0;  humidity=0;
- 
  level=0;  level=0;
- 
  }  }
- 
 } }
- 
 </code> </code>
code/capdac.1242776190.txt.gz · Last modified: 2009/05/19 23:36 by laurenceb
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