/*****************************************************************************
*
*
* File              USI_TWI_Master.h compiled with gcc
* Date              Friday, 10/31/08		Boo!
* Updated by        jkl
*
*
* Supported devices : All device with USI module can be used.
*                     The example is written for the ATtiny2313
*
* AppNote           : AVR310 - Using the USI module as a TWI Master
*
* This is modified to just do I2C communication on ATtiny2313 running at 
*	1MHz. Fast mode is probably possible, but would need a faster clock
*	and has not been tested.
*
*	12/15/08	Added declaration of USI_TWI_Start_Memory_Read	-jkl
****************************************************************************/
    
//********** Defines **********//

// Defines controlling timing limits - SCL <= 100KHz.

#if defined (__AVR_ATtiny45__) || defined (__AVR_ATtiny85__)
#define SYS_CLK   16500.0  // [kHz] Default for ATtiny2313

#elif defined (__AVR_ATtiny87__) || defined (__AVR_ATtiny167__)
#define SYS_CLK   16000.0  // [kHz] Default for ATtiny2313
#endif


// For use with _delay_us()
#define T2_TWI    5 		// >4,7us
#define T4_TWI    4 		// >4,0us

// Defines error code generating
//#define PARAM_VERIFICATION
//#define NOISE_TESTING
#define SIGNAL_VERIFY		// This should probably be on always.

/****************************************************************************
  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 TWI_NACK_BIT  0       // Bit position for (N)ACK bit.

// Note these have been renumbered from the Atmel Apps Note. Most likely errors are now
//		lowest numbers so they're easily recognized as LED flashes.
#define USI_TWI_NO_DATA             0x08  // Transmission buffer is empty
#define USI_TWI_DATA_OUT_OF_BOUND   0x09  // Transmission buffer is outside SRAM space
#define USI_TWI_UE_START_CON        0x07  // Unexpected Start Condition
#define USI_TWI_UE_STOP_CON         0x06  // Unexpected Stop Condition
#define USI_TWI_UE_DATA_COL         0x05  // Unexpected Data Collision (arbitration)
#define USI_TWI_NO_ACK_ON_DATA      0x02  // The slave did not acknowledge  all data
#define USI_TWI_NO_ACK_ON_ADDRESS   0x01  // The slave did not acknowledge  the address
#define USI_TWI_MISSING_START_CON   0x03  // Generated Start Condition not detected on bus
#define USI_TWI_MISSING_STOP_CON    0x04  // Generated Stop Condition not detected on bus
#define USI_TWI_BAD_MEM_READ	    0x0A  // Error during external memory read

// Device dependant defines ADDED BACK IN FROM ORIGINAL ATMEL .H

#if defined(__AVR_AT90Mega169__) | defined(__AVR_ATmega169__) | \
    defined(__AVR_AT90Mega165__) | defined(__AVR_ATmega165__) | \
    defined(__AVR_ATmega325__) | defined(__AVR_ATmega3250__) | \
    defined(__AVR_ATmega645__) | defined(__AVR_ATmega6450__) | \
    defined(__AVR_ATmega329__) | defined(__AVR_ATmega3290__) | \
    defined(__AVR_ATmega649__) | defined(__AVR_ATmega6490__)
    #define DDR_USI             DDRE
    #define PORT_USI            PORTE
    #define PIN_USI             PINE
    #define PORT_USI_SDA        PORTE5
    #define PORT_USI_SCL        PORTE4
    #define PIN_USI_SDA         PINE5
    #define PIN_USI_SCL         PINE4
#endif

#if defined(__AVR_ATtiny25__) | defined(__AVR_ATtiny45__) | defined(__AVR_ATtiny85__) | \
    defined(__AVR_AT90Tiny26__) | defined(__AVR_ATtiny26__) | defined(__AVR_ATtiny167__) | \
    defined(__AVR_ATtiny87__)
    #define DDR_USI             DDRB
    #define PORT_USI            PORTB
    #define PIN_USI             PINB
    #define PORT_USI_SDA        PORTB0
    #define PORT_USI_SCL        PORTB2
    #define PIN_USI_SDA         PINB0
    #define PIN_USI_SCL         PINB2
#endif

#if defined(__AVR_AT90Tiny2313__) | defined(__AVR_ATtiny2313__)
    #define DDR_USI             DDRB
    #define PORT_USI            PORTB
    #define PIN_USI             PINB
    #define PORT_USI_SDA        PORTB5
    #define PORT_USI_SCL        PORTB7
    #define PIN_USI_SDA         PINB5
    #define PIN_USI_SCL         PINB7
#endif

/* From the original .h
// Device dependant defines - These for ATtiny2313. // CHANGED FOR ATtiny85

    #define DDR_USI             DDRB
    #define PORT_USI            PORTB
    #define PIN_USI             PINB
    #define PORT_USI_SDA        PORTB0   // was PORTB5 - N/U
    #define PORT_USI_SCL        PORTB2   // was PORTB7 - N/U
    #define PIN_USI_SDA         PINB0    // was PINB5
    #define PIN_USI_SCL         PINB2    // was PINB7
*/

// General defines
#define TRUE  1
#define FALSE 0

//********** Prototypes **********//

void              USI_TWI_Master_Initialise( void );
unsigned char USI_TWI_Start_Random_Read( unsigned char * , unsigned char );
unsigned char USI_TWI_Start_Read_Write( unsigned char * , unsigned char );
unsigned char USI_TWI_Get_State_Info( void );
