306 lines
13 KiB
C
306 lines
13 KiB
C
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/*
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LUFA Library
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Copyright (C) Dean Camera, 2017.
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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 2017 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 disclaims 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_TWI_AVR8_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_TWI_AVR8_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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#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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* \attention 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,
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const uint8_t BitLength) ATTR_ALWAYS_INLINE;
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static inline void TWI_Init(const uint8_t Prescale,
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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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/** 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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uint16_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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uint16_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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