i2c.h

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#ifndef I2C_H
#define I2C_H



#include <avr/io.h>
#include <config.h>

/* 23/2/2011  svn 282  */


#define         TW_START   0x08
#define         TW_REP_START   0x10
#define         TW_MT_SLA_ACK   0x18
#define         TW_MT_SLA_NACK   0x20
#define         TW_MT_DATA_ACK   0x28
#define         TW_MT_DATA_NACK   0x30
#define         TW_MT_ARB_LOST   0x38
#define         TW_MR_ARB_LOST   0x38
#define         TW_MR_SLA_ACK   0x40
#define         TW_MR_SLA_NACK   0x48
#define         TW_MR_DATA_ACK   0x50
#define         TW_MR_DATA_NACK   0x58
#define         TW_ST_SLA_ACK   0xA8
#define         TW_ST_ARB_LOST_SLA_ACK   0xB0
#define         TW_ST_DATA_ACK   0xB8
#define         TW_ST_DATA_NACK   0xC0
#define         TW_ST_LAST_DATA   0xC8
#define         TW_SR_SLA_ACK   0x60
#define         TW_SR_ARB_LOST_SLA_ACK   0x68
#define         TW_SR_GCALL_ACK   0x70
#define         TW_SR_ARB_LOST_GCALL_ACK   0x78
#define         TW_SR_DATA_ACK   0x80
#define         TW_SR_DATA_NACK   0x88
#define         TW_SR_GCALL_DATA_ACK   0x90
#define         TW_SR_GCALL_DATA_NACK   0x98
#define         TW_SR_STOP   0xA0
#define         TW_NO_INFO   0xF8
#define         TW_BUS_ERROR   0x00



/* 

Return values from I2C for read,write,write-read
0       0       0       success
1       17      33      timeout waiting for start condition, device read
2       18      34      failed to send start
3       19      35      timeout waiting for send address
4       20      36      slave failed to ACK address
5                       arbitration lost
6                       other failure while expecting slave ACK address
7       23      39      timeout waiting for data sent
8       24      40      slave failed to ACK data
                41      timeout on repeated start
                42      failed to assert repeated start on bus
                43      timeout waiting for send address
                44      slave failed to ACK address
                45      arbitration lost
                46      other failure while expecting slave ACK address
                47      timeout waiting for data sent
                
*/





/* Note that there are no delays padding calls to these functions
 * If two calls occur in quick succession, you must add a delay (10uS should be plenty) to allow the
 * bus to recover. 
 *  You MUST also initialise the I2C bus registers TWSR and TWBR. For 8MHz :
        TWCR = 0x04 ;                                                   // Enable TWI. Overrides IO definitions
        TWSR = 2 ;                                                              // Clock rate is 8000000/(16 + 2xTWBR * 4 ^ TWSR)
        TWBR = 2 ;                                                              // = 8000000/(16 + (4 * 16)) = 100kHz
 */
 
 
void i2c_timerproc (void); 
 

uint8_t read_i2c_device(uint8_t address, uint8_t bytes, uint8_t *rdata);



uint8_t write_i2c_device(uint8_t address, uint8_t bytes, uint8_t *wdata);



uint8_t write_read_i2c_device(uint8_t address, uint8_t wbytes, uint8_t *wdata, uint8_t rbytes, uint8_t *rdata);

#endif