48 lines
934 B
C
48 lines
934 B
C
#include "i2c.h"
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#define F_CPU 16000000UL
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#define F_SCL 100000UL
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#define I2C_READ 1
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#define I2C_WRITE 0
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#define SCL_CLOCK ((F_CPU/F_SCL)-16)/2
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void i2c_init(void)
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{
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TWBR = (uint8_t)SCL_CLOCK;
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}
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void i2c_start(void)
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{
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// transmit START condition
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TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
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// wait for end of transmission
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while (!(TWCR & (1<<TWINT)));
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}
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void i2c_stop(void)
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{
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// transmit STOP condition
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TWCR = (1<<TWINT) | (1<<TWSTO) | (1<<TWEN);
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// wait for end of transmission
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while ((TWCR & (1<<TWSTO)));
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}
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void i2c_write_byte(uint8_t byte)
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{
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// transmit data
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TWDR = byte;
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TWCR = (1<<TWINT) | (1<<TWEN);
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// wait for end of transmission
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while (!(TWCR & (1<<TWINT)));
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}
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uint8_t i2c_read_byte(uint8_t ack)
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{
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// receive data
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TWCR = (1<<TWINT) | (1<<TWEN) | (ack<<TWEA);
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// wait for end of transmission
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while (!(TWCR & (1<<TWINT)));
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return TWDR;
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} |