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-
- #include <inttypes.h>
- #include <compat/twi.h>
-
- #include "twi.h"
-
-
- #ifndef F_CPU
- #define F_CPU 16000000UL
- #endif
-
-
- #define SCL_CLOCK 400000L
-
-
-
- void i2c_init(void)
- {
-
-
- TWSR = 0;
- TWBR = ((F_CPU/SCL_CLOCK)-16)/2;
-
- }
-
-
-
- unsigned char i2c_start(unsigned char address)
- {
- uint8_t twst;
-
-
- TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
-
-
- while(!(TWCR & (1<<TWINT)));
-
-
- twst = TW_STATUS & 0xF8;
- if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;
-
-
- TWDR = address;
- TWCR = (1<<TWINT) | (1<<TWEN);
-
-
- while(!(TWCR & (1<<TWINT)));
-
-
- twst = TW_STATUS & 0xF8;
- if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;
-
- return 0;
-
- }
-
-
-
- void i2c_start_wait(unsigned char address)
- {
- uint8_t twst;
-
-
- while ( 1 )
- {
-
- TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
-
-
- while(!(TWCR & (1<<TWINT)));
-
-
- twst = TW_STATUS & 0xF8;
- if ( (twst != TW_START) && (twst != TW_REP_START)) continue;
-
-
- TWDR = address;
- TWCR = (1<<TWINT) | (1<<TWEN);
-
-
- while(!(TWCR & (1<<TWINT)));
-
-
- twst = TW_STATUS & 0xF8;
- if ( (twst == TW_MT_SLA_NACK )||(twst ==TW_MR_DATA_NACK) )
- {
-
- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
-
-
- while(TWCR & (1<<TWSTO));
-
- continue;
- }
-
- break;
- }
-
- }
-
-
-
- unsigned char i2c_rep_start(unsigned char address)
- {
- return i2c_start( address );
-
- }
-
-
-
- void i2c_stop(void)
- {
-
- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
-
-
- while(TWCR & (1<<TWSTO));
-
- }
-
-
-
- unsigned char i2c_write( unsigned char data )
- {
- uint8_t twst;
-
-
- TWDR = data;
- TWCR = (1<<TWINT) | (1<<TWEN);
-
-
- while(!(TWCR & (1<<TWINT)));
-
-
- twst = TW_STATUS & 0xF8;
- if( twst != TW_MT_DATA_ACK) return 1;
- return 0;
-
- }
-
-
-
- unsigned char i2c_readAck(void)
- {
- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
- while(!(TWCR & (1<<TWINT)));
-
- return TWDR;
-
- }
-
-
-
- unsigned char i2c_readNak(void)
- {
- TWCR = (1<<TWINT) | (1<<TWEN);
- while(!(TWCR & (1<<TWINT)));
-
- return TWDR;
-
- }
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