main.c

avr 单片机TWI主模式中断方式源码,给大家参考

/*****************************************************************************
*
* Atmel Corporation
*
* File              : main.c
* Compiler          : IAR EWAAVR 2.28a/3.10c
* Revision          : $Revision: 1.13 $
* Date              : $Date: 24. mai 2004 11:31:20 $
* Updated by        : $Author: ltwa $
*
* Support mail      : [e-mail]
*
* Supported devices : All devices with a TWI module can be used.
*                     The example is written for the ATmega16
*
* AppNote           : AVR315 - TWI Master Implementation
*
* Description       : Example of how to use the driver for TWI master 
*                     communication.
*                     This code reads PORTD and sends the status to the TWI slave.
*                     Then it reads data from the slave and puts the data on PORTB.
*                     To run the example use STK500 and connect PORTB to the LEDS,
*                     and PORTD to the switches. .
*
****************************************************************************/

#include <ioavr.h>
#include <inavr.h>
#include "TWI_Master.h"

#define TWI_GEN_CALL         0x00  // The General Call address is 0

// Sample TWI transmission commands
#define TWI_CMD_MASTER_WRITE 0x10
#define TWI_CMD_MASTER_READ  0x20

// Sample TWI transmission states, used in the main application.
#define SEND_DATA             0x01
#define REQUEST_DATA          0x02
#define READ_DATA_FROM_BUFFER 0x03

unsigned char TWI_Act_On_Failure_In_Last_Transmission ( unsigned char TWIerrorMsg )
{
                    // A failure has occurred, use TWIerrorMsg to determine the nature of the failure
                    // and take appropriate actions.
                    // Se header file for a list of possible failures messages.
                    
                    // Here is a simple sample, where if received a NACK on the slave address,
                    // then a retransmission will be initiated.
 
  if ( (TWIerrorMsg == TWI_MTX_ADR_NACK) | (TWIerrorMsg == TWI_MRX_ADR_NACK) )
    TWI_Start_Transceiver();
    
  return TWIerrorMsg; 
}


void main( void )
{
  unsigned char messageBuf[4];
  unsigned char TWI_targetSlaveAddress, temp, TWI_operation=0,
                pressedButton, myCounter=0;

  //LED feedback port - connect port B to the STK500 LEDS
  DDRB  = 0xFF;
  PORTB = myCounter;
  
  //Switch port - connect portD to the STK500 switches
  DDRD  = 0x00;

  TWI_Master_Initialise();
  __enable_interrupt();
  
  TWI_targetSlaveAddress   = 0x10;

  // This example is made to work together with the AVR311 TWI Slave application note and stk500.
  // In adition to connecting the TWI pins, also connect PORTB to the LEDS and PORTD to the switches.
  // The code reads the pins to trigger the action you request. There is an example sending a general call,
  // address call with Master Read and Master Write. The first byte in the transmission is used to send
  // commands to the TWI slave.

  // This is a stk500 demo example. The buttons on PORTD are used to control different TWI operations.
  for(;;)
  {  
    pressedButton = ~PIND;
    if (pressedButton)       // Check if any button is pressed
    {
      do{temp = ~PIND;}      // Wait until key released
      while (temp);
      
      switch ( pressedButton ) 
      {
        // Send a Generall Call
        case (1<<PD0):      
          messageBuf[0] = TWI_GEN_CALL;     // The first byte must always consit of General Call code or the TWI slave address.
          messageBuf[1] = 0xAA;             // The command or data to be included in the general call.
          TWI_Start_Transceiver_With_Data( messageBuf, 2 );
          break;

        // Send a Address Call, sending a command and data to the Slave          
        case (1<<PD1):      
          messageBuf[0] = (TWI_targetSlaveAddress<<TWI_ADR_BITS) | (FALSE<<TWI_READ_BIT); // The first byte must always consit of General Call code or the TWI slave address.
          messageBuf[1] = TWI_CMD_MASTER_WRITE;             // The first byte is used for commands.
          messageBuf[2] = myCounter;                        // The second byte is used for the data.
          TWI_Start_Transceiver_With_Data( messageBuf, 3 );
          break;

        // Send a Address Call, sending a request, followed by a resceive          
        case (1<<PD2):      
          // Send the request-for-data command to the Slave
          messageBuf[0] = (TWI_targetSlaveAddress<<TWI_ADR_BITS) | (FALSE<<TWI_READ_BIT); // The first byte must always consit of General Call code or the TWI slave address.
          messageBuf[1] = TWI_CMD_MASTER_READ;             // The first byte is used for commands.
          TWI_Start_Transceiver_With_Data( messageBuf, 2 );

          TWI_operation = REQUEST_DATA;         // To release resources to other operations while waiting for the TWI to complete,
                                                // we set a operation mode and continue this command sequence in a "followup" 
                                                // section further down in the code.
                    
        // Get status from Transceiver and put it on PORTB
        case (1<<PD5):
          PORTB = TWI_Get_State_Info();
          break;

        // Increment myCounter and put it on PORTB          
        case (1<<PD6):      
          PORTB = ++myCounter;        
          break;
          
        // Reset myCounter and put it on PORTB
        case (1<<PD7):      
          PORTB = myCounter = 0;        
          break;  
      }
    }    

    if ( ! TWI_Transceiver_Busy() )
    {
    // Check if the last operation was successful
      if ( TWI_statusReg.lastTransOK )
      {
        if ( TWI_operation ) // Section for follow-up operations.
        {
        // Determine what action to take now
          if (TWI_operation == REQUEST_DATA)
          { // Request/collect the data from the Slave
            messageBuf[0] = (TWI_targetSlaveAddress<<TWI_ADR_BITS) | (TRUE<<TWI_READ_BIT); // The first byte must always consit of General Call code or the TWI slave address.
            TWI_Start_Transceiver_With_Data( messageBuf, 2 );       
            TWI_operation = READ_DATA_FROM_BUFFER; // Set next operation        
          }
          else if (TWI_operation == READ_DATA_FROM_BUFFER)
          { // Get the received data from the transceiver buffer
            TWI_Get_Data_From_Transceiver( messageBuf, 2 );
            PORTB = messageBuf[1];        // Store data on PORTB.
            TWI_operation = FALSE;        // Set next operation        
          }
        }
      }
      else // Got an error during the last transmission
      {
        // Use TWI status information to detemine cause of failure and take appropriate actions. 
        TWI_Act_On_Failure_In_Last_Transmission( TWI_Get_State_Info( ) );
      }
    }

    // Do something else while waiting for TWI operation to complete and/or a switch to be pressed
    __no_operation(); // Put own code here.

  }
}


/*
  // This example code runs forever; sends a byte to the slave, then requests a byte
  // from the slave and stores it on PORTB, and starts over again. Since it is interupt
  // driven one can do other operations while waiting for the transceiver to complete.
  
  // Send initial data to slave
  messageBuf[0] = (TWI_targetSlaveAddress<<TWI_ADR_BITS) | (FALSE<<TWI_READ_BIT);
  messageBuf[1] = 0x00;
  TWI_Start_Transceiver_With_Data( messageBuf, 2 );

  TWI_operation = REQUEST_DATA; // Set the next operation

  for (;;)
  {
    // Check if the TWI Transceiver has completed an operation.
    if ( ! TWI_Transceiver_Busy() )                              
    {
    // Check if the last operation was successful
      if ( TWI_statusReg.lastTransOK )
      {
      // Determine what action to take now
        if (TWI_operation == SEND_DATA)
        { // Send data to slave
          messageBuf[0] = (TWI_targetSlaveAddress<<TWI_ADR_BITS) | (FALSE<<TWI_READ_BIT);
          TWI_Start_Transceiver_With_Data( messageBuf, 2 );
          
          TWI_operation = REQUEST_DATA; // Set next operation
        }
        else if (TWI_operation == REQUEST_DATA)
        { // Request data from slave
          messageBuf[0] = (TWI_targetSlaveAddress<<TWI_ADR_BITS) | (TRUE<<TWI_READ_BIT);
          TWI_Start_Transceiver_With_Data( messageBuf, 2 );
          
          TWI_operation = READ_DATA_FROM_BUFFER; // Set next operation        
        }
        else if (TWI_operation == READ_DATA_FROM_BUFFER)
        { // Get the received data from the transceiver buffer
          TWI_Get_Data_From_Transceiver( messageBuf, 2 );
          PORTB = messageBuf[1];        // Store data on PORTB.
          
          TWI_operation = SEND_DATA;    // Set next operation        
        }
      }
      else // Got an error during the last transmission
      {
        // Use TWI status information to detemine cause of failure and take appropriate actions. 
        TWI_Act_On_Failure_In_Last_Transmission( TWI_Get_State_Info( ) );
      }
    }
    // Do something else while waiting for the TWI Transceiver to complete the current operation
    __no_operation(); // Put own code here.
  }
}
*/