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/*
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             LUFA Library
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     Copyright (C) Dean Camera, 2011.
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  dean [at] fourwalledcubicle [dot] com
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           www.lufa-lib.org
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*/
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/*
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  Copyright 2011  Dean Camera (dean [at] fourwalledcubicle [dot] com)
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  Permission to use, copy, modify, distribute, and sell this
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  software and its documentation for any purpose is hereby granted
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  without fee, provided that the above copyright notice appear in
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  all copies and that both that the copyright notice and this
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  permission notice and warranty disclaimer appear in supporting
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  documentation, and that the name of the author not be used in
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  advertising or publicity pertaining to distribution of the
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  software without specific, written prior permission.
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  The author disclaim all warranties with regard to this
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  software, including all implied warranties of merchantability
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  and fitness.  In no event shall the author be liable for any
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  special, indirect or consequential damages or any damages
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  whatsoever resulting from loss of use, data or profits, whether
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  in an action of contract, negligence or other tortious action,
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  arising out of or in connection with the use or performance of
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  this software.
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*/
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/** \file
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 *  \brief TWI Peripheral Driver (AVR8)
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 *
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 *  On-chip TWI driver for the 8-bit AVR microcontrollers.
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 *
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 *  \note This file should not be included directly. It is automatically included as needed by the TWI driver
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 *        dispatch header located in LUFA/Drivers/Peripheral/TWI.h.
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 */
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/** \ingroup Group_TWI
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 *  \defgroup Group_TWI_AVR8 TWI Peripheral Driver (AVR8)
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 *
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 *  \section Sec_ModDescription Module Description
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 *  Master mode TWI driver for the 8-bit AVR microcontrollers which contain a hardware TWI module.
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 *
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 *  \note This file should not be included directly. It is automatically included as needed by the TWI driver
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 *        dispatch header located in LUFA/Drivers/Peripheral/TWI.h.
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 *
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 *  \section Sec_ExampleUsage Example Usage
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 *  The following snippet is an example of how this module may be used within a typical
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 *  application.
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 *
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 *  <b>Low Level API Example:</b>
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 *  \code
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 *      // Initialize the TWI driver before first use at 200KHz
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 *      TWI_Init(TWI_BIT_PRESCALE_1, TWI_BITLENGTH_FROM_FREQ(1, 200000));
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 *
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 *      // Start a write session to device at device address 0xA0, internal address 0xDC with a 10ms timeout
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 *      if (TWI_StartTransmission(0xA0 | TWI_ADDRESS_WRITE, 10) == TWI_ERROR_NoError)
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 *      {
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 *          TWI_SendByte(0xDC);
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 *
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 *          TWI_SendByte(0x01);
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 *          TWI_SendByte(0x02);
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 *          TWI_SendByte(0x03);
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 *
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 *          // Must stop transmission afterwards to release the bus
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 *          TWI_StopTransmission();
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 *      }
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 *
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 *      // Start a read session to device at address 0xA0, internal address 0xDC with a 10ms timeout
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 *      if (TWI_StartTransmission(0xA0 | TWI_ADDRESS_WRITE, 10) == TWI_ERROR_NoError)
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 *      {
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 *          TWI_SendByte(0xDC);
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 *          TWI_StopTransmission();
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 *
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 *          if (TWI_StartTransmission(0xA0 | TWI_ADDRESS_READ, 10) == TWI_ERROR_NoError)
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 *          {
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 *              uint8_t Byte1, Byte2, Byte3;
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 *
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 *              // Read three bytes, acknowledge after the third byte is received
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 *              TWI_ReceiveByte(&Byte1, false);
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 *              TWI_ReceiveByte(&Byte2, false);
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 *              TWI_ReceiveByte(&Byte3, true);
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 *
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 *              // Must stop transmission afterwards to release the bus
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 *              TWI_StopTransmission();
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 *          }
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 *      }
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 *  \endcode
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 * 
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 *  <b>High Level API Example:</b>
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 *  \code
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 *      // Initialize the TWI driver before first use at 200KHz
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 *      TWI_Init(TWI_BIT_PRESCALE_1, TWI_BITLENGTH_FROM_FREQ(1, 200000));
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 *
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 *      // Start a write session to device at device address 0xA0, internal address 0xDC with a 10ms timeout
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 *      uint8_t InternalWriteAddress = 0xDC;
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 *      uint8_t WritePacket[3] = {0x01, 0x02, 0x03};
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 *
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 *      TWI_WritePacket(0xA0, 10, &InternalWriteAddress, sizeof(InternalWriteAddress),
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 *                      &WritePacket, sizeof(WritePacket);
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 *
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 *      // Start a read session to device at address 0xA0, internal address 0xDC with a 10ms timeout
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 *      uint8_t InternalReadAddress = 0xDC;
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 *      uint8_t ReadPacket[3];
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 *
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 *      TWI_ReadPacket(0xA0, 10, &InternalReadAddress, sizeof(InternalReadAddress),
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 *                     &ReadPacket, sizeof(ReadPacket);
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 *  \endcode
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 *
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 *  @{
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 */
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#ifndef __TWI_AVR8_H__
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#define __TWI_AVR8_H__
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        /* Includes: */
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                #include "../../../Common/Common.h"
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                #include <stdio.h>
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                #include <util/twi.h>
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        /* Enable C linkage for C++ Compilers: */
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                #if defined(__cplusplus)
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                        extern "C" {
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                #endif
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        /* Preprocessor Checks: */
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                #if !defined(__INCLUDE_FROM_TWI_H) && !defined(__INCLUDE_FROM_TWI_C)
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                        #error Do not include this file directly. Include LUFA/Drivers/Peripheral/TWI.h instead.
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                #endif
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                #if !(defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB646__) || \
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                      defined(__AVR_AT90USB1287__) || defined(__AVR_AT90USB647__) || \
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                          defined(__AVR_ATmega16U4__)  || defined(__AVR_ATmega32U4__) || \
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                          defined(__AVR_ATmega32U6__))
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                        #error The TWI peripheral driver is not currently available for your selected microcontroller model.
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                #endif
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        /* Public Interface - May be used in end-application: */
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                /* Macros: */
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                        /** TWI slave device address mask for a read session. Mask with a slave device base address to obtain
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                         *  the correct TWI bus address for the slave device when reading data from it.
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                         */
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                        #define TWI_ADDRESS_READ         0x01
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                        /** TWI slave device address mask for a write session. Mask with a slave device base address to obtain
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                         *  the correct TWI bus address for the slave device when writing data to it.
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                         */
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                        #define TWI_ADDRESS_WRITE        0x00
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                        /** Mask to retrieve the base address for a TWI device, which can then be ORed with \ref TWI_ADDRESS_READ
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                         *  or \ref TWI_ADDRESS_WRITE to obtain the device's read and write address respectively.
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                         */
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                        #define TWI_DEVICE_ADDRESS_MASK  0xFE
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                        /** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 1. */
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                        #define TWI_BIT_PRESCALE_1       ((0 << TWPS1) | (0 << TWPS0))
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                        /** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 4. */
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                        #define TWI_BIT_PRESCALE_4       ((0 << TWPS1) | (1 << TWPS0))
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                        /** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 16. */
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                        #define TWI_BIT_PRESCALE_16      ((1 << TWPS1) | (0 << TWPS0))
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                        /** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 64. */
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                        #define TWI_BIT_PRESCALE_64      ((1 << TWPS1) | (1 << TWPS0))
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                        /** Calculates the length of each bit on the TWI bus for a given target frequency. This may be used with
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                         *  the \ref TWI_Init() function to convert a bus frequency to a number of clocks for the \c BitLength
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                         *  parameter.
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                         *
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                         *  \param[in] Prescale   Prescaler set on the TWI bus.
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                         *  \param[in] Frequency  Desired TWI bus frequency in Hz.
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                         *
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                         *  \return Bit length in clocks for the given TWI bus frequency at the given prescaler value.
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                         */
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                        #define TWI_BITLENGTH_FROM_FREQ(Prescale, Frequency) ((((F_CPU / (Prescale)) / (Frequency)) - 16) / 2)
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                /* Enums: */
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                        /** Enum for the possible return codes of the TWI transfer start routine and other dependant TWI functions. */
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                        enum TWI_ErrorCodes_t
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                        {
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                                TWI_ERROR_NoError              = 0, /**< Indicates that the command completed successfully. */
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                                TWI_ERROR_BusFault             = 1, /**< A TWI bus fault occurred while attempting to capture the bus. */
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                                TWI_ERROR_BusCaptureTimeout    = 2, /**< A timeout occurred whilst waiting for the bus to be ready. */
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                                TWI_ERROR_SlaveResponseTimeout = 3, /**< No ACK received at the nominated slave address within the timeout period. */
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                                TWI_ERROR_SlaveNotReady        = 4, /**< Slave NAKed the TWI bus START condition. */
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                                TWI_ERROR_SlaveNAK             = 5, /**< Slave NAKed whilst attempting to send data to the device. */
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                        };
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                /* Inline Functions: */
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                        /** Initializes the TWI hardware into master mode, ready for data transmission and reception. This must be
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                         *  before any other TWI operations.
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                         *
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                         *  The generated SCL frequency will be according to the formula <pre>F_CPU / (16 + 2 * BitLength + 4 ^ Prescale)</pre>.
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                         *
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                         *  \note The value of the \c BitLength parameter should not be set below 10 or invalid bus conditions may
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                         *        occur, as indicated in the AVR8 microcontroller datasheet.
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                         *
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                         *  \param[in] Prescale   Prescaler to use when determining the bus frequency, a \c TWI_BIT_PRESCALE_* value.
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                         *  \param[in] BitLength  Length of the bits sent on the bus.
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                         */
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                        static inline void TWI_Init(const uint8_t Prescale, const uint8_t BitLength) ATTR_ALWAYS_INLINE;
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                        static inline void TWI_Init(const uint8_t Prescale, const uint8_t BitLength)
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                        {
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                                TWCR |= (1 << TWEN);
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                                TWSR  = Prescale;
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                                TWBR  = BitLength;
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                        }
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                        /** Turns off the TWI driver hardware. If this is called, any further TWI operations will require a call to
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                         *  \ref TWI_Init() before the TWI can be used again.
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                         */
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                        static inline void TWI_Disable(void) ATTR_ALWAYS_INLINE;
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                        static inline void TWI_Disable(void)
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                        {
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                                TWCR &= ~(1 << TWEN);
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                        }
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                        /** Sends a TWI STOP onto the TWI bus, terminating communication with the currently addressed device. */
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                        static inline void TWI_StopTransmission(void) ATTR_ALWAYS_INLINE;
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                        static inline void TWI_StopTransmission(void)
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                        {
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                                TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
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                        }
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                /* Function Prototypes: */
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                        /** Begins a master mode TWI bus communication with the given slave device address.
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                         *
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                         *  \param[in] SlaveAddress  Address of the slave TWI device to communicate with.
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                         *  \param[in] TimeoutMS     Timeout period within which the slave must respond, in milliseconds.
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                         *
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                         *  \return A value from the \ref TWI_ErrorCodes_t enum.
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                         */
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                        uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
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                                                      const uint8_t TimeoutMS);
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                        /** Sends a byte to the currently addressed device on the TWI bus.
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                         *
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                         *  \param[in] Byte  Byte to send to the currently addressed device
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                         *
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                         *  \return Boolean \c true if the recipient ACKed the byte, \c false otherwise
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                         */
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                        bool TWI_SendByte(const uint8_t Byte);
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                        /** Receives a byte from the currently addressed device on the TWI bus.
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                         *
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                         *  \param[in] Byte      Location where the read byte is to be stored.
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                         *  \param[in] LastByte  Indicates if the byte should be ACKed if false, NAKed if true.
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                         *
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                         *  \return Boolean \c true if the byte reception successfully completed, \c false otherwise.
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                         */
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                        bool TWI_ReceiveByte(uint8_t* const Byte,
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                                             const bool LastByte) ATTR_NON_NULL_PTR_ARG(1);
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                        bool TWI_ReceiveByte(uint8_t* const Byte,
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                                             const bool LastByte);
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                        /** High level function to perform a complete packet transfer over the TWI bus to the specified
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                         *  device.
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                         *
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                         *  \param[in] SlaveAddress        Base address of the TWI slave device to communicate with.
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                         *  \param[in] TimeoutMS           Timeout for bus capture and slave START ACK, in milliseconds.
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                         *  \param[in] InternalAddress     Pointer to a location where the internal slave read start address is stored.
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                         *  \param[in] InternalAddressLen  Size of the internal device address, in bytes.
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                         *  \param[in] Buffer              Pointer to a buffer where the read packet data is to be stored.
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                         *  \param[in] Length              Size of the packet to read, in bytes.
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                         *
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                         *  \return A value from the \ref TWI_ErrorCodes_t enum.
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                         */
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                        uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
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                                               const uint8_t TimeoutMS,
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                                               const uint8_t* InternalAddress,
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                                               uint8_t InternalAddressLen,
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                                               uint8_t* Buffer,
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                                               uint8_t Length) ATTR_NON_NULL_PTR_ARG(3);
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                        /** High level function to perform a complete packet transfer over the TWI bus from the specified
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                         *  device.
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                         *
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                         *  \param[in] SlaveAddress        Base address of the TWI slave device to communicate with
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                         *  \param[in] TimeoutMS           Timeout for bus capture and slave START ACK, in milliseconds
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                         *  \param[in] InternalAddress     Pointer to a location where the internal slave write start address is stored
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                         *  \param[in] InternalAddressLen  Size of the internal device address, in bytes
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                         *  \param[in] Buffer              Pointer to a buffer where the packet data to send is stored
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                         *  \param[in] Length              Size of the packet to send, in bytes
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                         *
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                         *  \return A value from the \ref TWI_ErrorCodes_t enum.
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                         */
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                        uint8_t TWI_WritePacket(const uint8_t SlaveAddress,
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                                                const uint8_t TimeoutMS,
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                                                const uint8_t* InternalAddress,
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                                                uint8_t InternalAddressLen,
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                                                const uint8_t* Buffer,
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                                                uint8_t Length) ATTR_NON_NULL_PTR_ARG(3);
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        /* Disable C linkage for C++ Compilers: */
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                #if defined(__cplusplus)
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                        }
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                #endif
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#endif
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/** @} */
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