twi.h File Reference

#include <avr/io.h>

Go to the source code of this file.

Macros
Definition of frequencies
#define	F_CPU   16000000
	CPU frequency in Hz required TWI_BIT_RATE_REG.
#define	F_SCL   100000
	I2C/TWI bit rate. Must be greater than 31000.
#define	TWI_BIT_RATE_REG   ((F_CPU/F_SCL - 16) / 2)
	TWI bit rate register value.
Definition of ports and pins
#define	TWI_PORT   PORTC
	Port of TWI unit.
#define	TWI_SDA_PIN   4
	SDA pin of TWI unit.
#define	TWI_SCL_PIN   5
	SCL pin of TWI unit.

Other definitions
#define	TWI_WRITE   0
	Mode for writing to I2C/TWI device.
#define	TWI_READ   1
	Mode for reading from I2C/TWI device.
#define	TWI_ACK   0
	ACK value for writing to I2C/TWI bus.
#define	TWI_NACK   1
	NACK value for writing to I2C/TWI bus.
#define	DDR(_x)
	Address of Data Direction Register of port _x.
#define	PIN(_x)
	Address of input register of port _x.
void	twi_init (void)
	Initialize TWI unit, enable internal pull-ups, and set SCL frequency.
void	twi_start (void)
	Start communication on I2C/TWI bus.
uint8_t	twi_write (uint8_t data)
	Write one byte to the I2C/TWI bus.
uint8_t	twi_read (uint8_t ack)
	Read one byte from the I2C/TWI bus and acknowledge it by ACK or NACK.
void	twi_stop (void)
	Generates Stop condition on I2C/TWI bus.
uint8_t	twi_test_address (uint8_t addr)
	Test presence of one I2C device on the bus.
void	twi_readfrom_mem_into (uint8_t addr, uint8_t memaddr, volatile uint8_t *buf, uint8_t nbytes)
	Read into buf from the peripheral, starting from the memory address.