TWI_Master.h

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/*****************************************************************************
*
* Atmel Corporation
*
* File              : TWI_Master.h
* Compiler          : IAR EWAAVR 2.28a/3.10c
* Revision          : $Revision: 1.13 $
* Date              : $Date: 24. mai 2004 11:31:22 $
* Updated by        : $Author: ltwa $
*
* Support mail      : avr@atmel.com
*
* Supported devices : All devices with a TWI module can be used.
*                     The example is written for the ATmega16
*
* AppNote           : AVR315 - TWI Master Implementation
*
* Description       : Header file for TWI_Master.c
*                     Include this file in the application.
*
****************************************************************************/

/****************************************************************************
  TWI Status/Control register definitions
****************************************************************************/
#define TWI_BUFFER_SIZE 4   // Set this to the largest message size that will be sent including address byte.

#define TWI_TWBR            0x0C        // TWI Bit rate Register setting.
                                        // Se Application note for detailed 
                                        // information on setting this value.
// Not used defines!
//#define TWI_TWPS          0x00        // This driver presumes prescaler = 00

/****************************************************************************
  Global definitions
****************************************************************************/

union TWI_statusReg                       // Status byte holding flags.
{
    unsigned char all;
    struct
    {
        unsigned char lastTransOK:1;      
        unsigned char unusedBits:7;
    };
};

extern union TWI_statusReg TWI_statusReg;

/****************************************************************************
  Function definitions
****************************************************************************/
void TWI_Master_Initialise( void );
unsigned char TWI_Transceiver_Busy( void );
unsigned char TWI_Get_State_Info( void );
void TWI_Start_Transceiver_With_Data( unsigned char * , unsigned char );
void TWI_Start_Transceiver( void );
unsigned char TWI_Get_Data_From_Transceiver( unsigned char *, unsigned char );

/****************************************************************************
  Bit and byte definitions
****************************************************************************/
#define TWI_READ_BIT  0       // Bit position for R/W bit in "address byte".
#define TWI_ADR_BITS  1       // Bit position for LSB of the slave address bits in the init byte.

#define TRUE          1
#define FALSE         0

/****************************************************************************
  TWI State codes
****************************************************************************/
// General TWI Master staus codes                      
#define TWI_START                  0x08  // START has been transmitted  
#define TWI_REP_START              0x10  // Repeated START has been transmitted
#define TWI_ARB_LOST               0x38  // Arbitration lost

// TWI Master Transmitter staus codes                      
#define TWI_MTX_ADR_ACK            0x18  // SLA+W has been tramsmitted and ACK received
#define TWI_MTX_ADR_NACK           0x20  // SLA+W has been tramsmitted and NACK received 
#define TWI_MTX_DATA_ACK           0x28  // Data byte has been tramsmitted and ACK received
#define TWI_MTX_DATA_NACK          0x30  // Data byte has been tramsmitted and NACK received 

// TWI Master Receiver staus codes  
#define TWI_MRX_ADR_ACK            0x40  // SLA+R has been tramsmitted and ACK received
#define TWI_MRX_ADR_NACK           0x48  // SLA+R has been tramsmitted and NACK received
#define TWI_MRX_DATA_ACK           0x50  // Data byte has been received and ACK tramsmitted
#define TWI_MRX_DATA_NACK          0x58  // Data byte has been received and NACK tramsmitted

// TWI Slave Transmitter staus codes
#define TWI_STX_ADR_ACK            0xA8  // Own SLA+R has been received; ACK has been returned
#define TWI_STX_ADR_ACK_M_ARB_LOST 0xB0  // Arbitration lost in SLA+R/W as Master; own SLA+R has been received; ACK has been returned
#define TWI_STX_DATA_ACK           0xB8  // Data byte in TWDR has been transmitted; ACK has been received
#define TWI_STX_DATA_NACK          0xC0  // Data byte in TWDR has been transmitted; NOT ACK has been received
#define TWI_STX_DATA_ACK_LAST_BYTE 0xC8  // Last data byte in TWDR has been transmitted (TWEA = “0”); ACK has been received

// TWI Slave Receiver staus codes
#define TWI_SRX_ADR_ACK            0x60  // Own SLA+W has been received ACK has been returned
#define TWI_SRX_ADR_ACK_M_ARB_LOST 0x68  // Arbitration lost in SLA+R/W as Master; own SLA+W has been received; ACK has been returned
#define TWI_SRX_GEN_ACK            0x70  // General call address has been received; ACK has been returned
#define TWI_SRX_GEN_ACK_M_ARB_LOST 0x78  // Arbitration lost in SLA+R/W as Master; General call address has been received; ACK has been returned
#define TWI_SRX_ADR_DATA_ACK       0x80  // Previously addressed with own SLA+W; data has been received; ACK has been returned
#define TWI_SRX_ADR_DATA_NACK      0x88  // Previously addressed with own SLA+W; data has been received; NOT ACK has been returned
#define TWI_SRX_GEN_DATA_ACK       0x90  // Previously addressed with general call; data has been received; ACK has been returned
#define TWI_SRX_GEN_DATA_NACK      0x98  // Previously addressed with general call; data has been received; NOT ACK has been returned
#define TWI_SRX_STOP_RESTART       0xA0  // A STOP condition or repeated START condition has been received while still addressed as Slave

// TWI Miscellaneous status codes
#define TWI_NO_STATE               0xF8  // No relevant state information available; TWINT = “0”
#define TWI_BUS_ERROR              0x00  // Bus error due to an illegal START or STOP condition