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137 lines
4.2 KiB
137 lines
4.2 KiB
#ifndef GUARD_I2CMASTER_H
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#define GUARDG_I2CMASTER_H
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/*************************************************************************
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* Title: C include file for the I2C master interface
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* (i2cmaster.S or twimaster.c)
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* Author: Peter Fleury <pfleury@gmx.ch>
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* File: $Id: i2cmaster.h,v 1.12 2015/09/16 09:27:58 peter Exp $
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* Software: AVR-GCC 4.x
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* Target: any AVR device
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* Usage: see Doxygen manual
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**************************************************************************/
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/**
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@file
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@defgroup pfleury_ic2master I2C Master library
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@code #include <i2cmaster.h> @endcode
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@brief I2C (TWI) Master Software Library
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Basic routines for communicating with I2C slave devices. This single master
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implementation is limited to one bus master on the I2C bus.
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This I2c library is implemented as a compact assembler software implementation of the I2C protocol
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which runs on any AVR (i2cmaster.S) and as a TWI hardware interface for all AVR with built-in TWI hardware (twimaster.c).
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Since the API for these two implementations is exactly the same, an application can be linked either against the
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software I2C implementation or the hardware I2C implementation.
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Use 4.7k pull-up resistor on the SDA and SCL pin.
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Adapt the SCL and SDA port and pin definitions and eventually the delay routine in the module
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i2cmaster.S to your target when using the software I2C implementation !
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Adjust the CPU clock frequence F_CPU in twimaster.c or in the Makfile when using the TWI hardware implementaion.
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@note
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The module i2cmaster.S is based on the Atmel Application Note AVR300, corrected and adapted
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to GNU assembler and AVR-GCC C call interface.
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Replaced the incorrect quarter period delays found in AVR300 with
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half period delays.
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@author Peter Fleury pfleury@gmx.ch http://tinyurl.com/peterfleury
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@copyright (C) 2015 Peter Fleury, GNU General Public License Version 3
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- modified for better readability and error return codes
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*/
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/**@{*/
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#if (__GNUC__ * 100 + __GNUC_MINOR__) < 304
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#error "This library requires AVR-GCC 3.4 or later, update to newer AVR-GCC compiler !"
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#endif
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#include <stdint.h>
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/** defines the data direction (reading from I2C device) in i2c_start(),i2c_rep_start() */
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#define I2C_READ 1
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/** defines the data direction (writing to I2C device) in i2c_start(),i2c_rep_start() */
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#define I2C_WRITE 0
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#define TWI_BUS_PORT PORTD //PORTC
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#define TWI_BUS_DDR DDRD //DDRC
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#define SDA PD1 //PC1
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#define SCL PD0 //PC0
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/**
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@brief initialize the I2C master interace. Need to be called only once
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@return none
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*/
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void initI2C(void);
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/**
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@brief Terminates the data transfer and releases the I2C bus
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@return none
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*/
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void i2cStop(void);
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/**
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@brief Issues a start condition and sends address and transfer direction
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@param addr address and transfer direction of I2C device
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@retval 0 device accessible
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@retval 1 failed to access device
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*/
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uint8_t i2cStart(uint8_t addr);
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/**
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@brief Issues a repeated start condition and sends address and transfer direction
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@param addr address and transfer direction of I2C device
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@retval 0 device accessible
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@retval 1 failed to access device
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*/
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uint8_t i2cRepeatStart(uint8_t addr);
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/**
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@brief Issues a start condition and sends address and transfer direction
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If device is busy, use ack polling to wait until device ready
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@param addr address and transfer direction of I2C device
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@return none
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*/
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void i2cStartWait(uint8_t addr);
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/**
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@brief Send one byte to I2C device
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@param data byte to be transfered
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@retval 0 write successful
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@retval 1 write failed
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*/
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uint8_t i2cWrite(uint8_t data);
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/**
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@brief read one byte from the I2C device, request more data from device
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@return byte read from I2C device
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*/
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uint8_t i2cReadAck(void);
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/**
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@brief read one byte from the I2C device, read is followed by a stop condition
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@return byte read from I2C device
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*/
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uint8_t i2cReadNak(void);
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/**
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@brief read one byte from the I2C device
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Implemented as a macro, which calls either @ref i2c_readAck or @ref i2c_readNak
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@param ack 1 send ack, request more data from device<br>
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0 send nak, read is followed by a stop condition
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@return byte read from I2C device
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*/
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uint8_t i2cRead(uint8_t ack);
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/**@}*/
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#endif
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