+
+ /* Enable C linkage for C++ Compilers: */
+ #if defined(__cplusplus)
+ extern "C" {
+ #endif
+
+ /* Preprocessor Checks: */
+ #if !defined(__INCLUDE_FROM_TWI_H) && !defined(__INCLUDE_FROM_TWI_C)
+ #error Do not include this file directly. Include LUFA/Drivers/Peripheral/TWI.h instead.
+ #endif
+
+ /* Public Interface - May be used in end-application: */
+ /* Macros: */
+ /** TWI slave device address mask for a read session. Mask with a slave device base address to obtain
+ * the correct TWI bus address for the slave device when reading data from it.
+ */
+ #define TWI_ADDRESS_READ 0x01
+
+ /** TWI slave device address mask for a write session. Mask with a slave device base address to obtain
+ * the correct TWI bus address for the slave device when writing data to it.
+ */
+ #define TWI_ADDRESS_WRITE 0x00
+
+ /** Mask to retrieve the base address for a TWI device, which can then be ORed with \ref TWI_ADDRESS_READ
+ * or \ref TWI_ADDRESS_WRITE to obtain the device's read and write address respectively.
+ */
+ #define TWI_DEVICE_ADDRESS_MASK 0xFE
+
+ /** Calculates the length of each bit on the TWI bus for a given target frequency. This may be used with
+ * the \ref TWI_Init() function to convert a bus frequency to a number of clocks for the \c BitLength
+ * parameter.
+ *
+ * \param[in] Frequency Desired TWI bus frequency in Hz.
+ *
+ * \return Bit length in clocks for the given TWI bus frequency at the given prescaler value.
+ */
+ #define TWI_BAUD_FROM_FREQ(Frequency) ((F_CPU / (2 * Frequency)) - 5)
+
+ /* Enums: */
+ /** Enum for the possible return codes of the TWI transfer start routine and other dependant TWI functions. */
+ enum TWI_ErrorCodes_t
+ {
+ TWI_ERROR_NoError = 0, /**< Indicates that the command completed successfully. */
+ TWI_ERROR_BusFault = 1, /**< A TWI bus fault occurred while attempting to capture the bus. */
+ TWI_ERROR_BusCaptureTimeout = 2, /**< A timeout occurred whilst waiting for the bus to be ready. */
+ TWI_ERROR_SlaveResponseTimeout = 3, /**< No ACK received at the nominated slave address within the timeout period. */
+ TWI_ERROR_SlaveNotReady = 4, /**< Slave NAKed the TWI bus START condition. */
+ TWI_ERROR_SlaveNAK = 5, /**< Slave NAKed whilst attempting to send data to the device. */
+ };
+
+ /* Inline Functions: */
+ /** Initializes the TWI hardware into master mode, ready for data transmission and reception. This must be
+ * before any other TWI operations.
+ *
+ * The generated SCL frequency will be according to the formula F_CPU / (2 * (5 + (BAUD)))
.
+ *
+ * \attention The value of the \c BitLength parameter should not be set below 10 or invalid bus conditions may
+ * occur, as indicated in the XMEGA microcontroller datasheet.
+ *
+ * \param[in] twi The TWI Peripheral to use
+ * \param[in] Baud Value of the BAUD register of the TWI Master.
+ */
+ static inline void TWI_Init(TWI_t *twi, const uint8_t Baud) ATTR_ALWAYS_INLINE ATTR_NON_NULL_PTR_ARG(1);
+ static inline void TWI_Init(TWI_t *twi, const uint8_t Baud)
+ {
+ twi->CTRL = 0x00;
+ twi->MASTER.BAUD = Baud;
+ twi->MASTER.CTRLA = TWI_MASTER_ENABLE_bm;
+ twi->MASTER.CTRLB = 0;
+ twi->MASTER.STATUS = TWI_MASTER_BUSSTATE_IDLE_gc;
+ }
+
+ /** Turns off the TWI driver hardware. If this is called, any further TWI operations will require a call to
+ * \ref TWI_Init() before the TWI can be used again.
+ *
+ * \param[in] twi The TWI Peripheral to use
+ */
+ static inline void TWI_Disable(TWI_t *twi) ATTR_ALWAYS_INLINE ATTR_NON_NULL_PTR_ARG(1);
+ static inline void TWI_Disable(TWI_t *twi)
+ {
+ twi->MASTER.CTRLA &= ~TWI_MASTER_ENABLE_bm;
+ }
+
+ /** Sends a TWI STOP onto the TWI bus, terminating communication with the currently addressed device.
+ *
+ * \param[in] twi The TWI Peripheral to use
+ */
+ static inline void TWI_StopTransmission(TWI_t *twi) ATTR_ALWAYS_INLINE ATTR_NON_NULL_PTR_ARG(1);
+ static inline void TWI_StopTransmission(TWI_t *twi)
+ {
+ twi->MASTER.CTRLC = TWI_MASTER_ACKACT_bm | TWI_MASTER_CMD_STOP_gc;
+ }
+
+ /* Function Prototypes: */
+ /** Begins a master mode TWI bus communication with the given slave device address.
+ *
+ * \param[in] twi The TWI Peripheral to use
+ * \param[in] SlaveAddress Address of the slave TWI device to communicate with.
+ * \param[in] TimeoutMS Timeout period within which the slave must respond, in milliseconds.
+ *
+ * \return A value from the \ref TWI_ErrorCodes_t enum.
+ */
+ uint8_t TWI_StartTransmission(TWI_t *twi,
+ const uint8_t SlaveAddress,
+ const uint8_t TimeoutMS) ATTR_NON_NULL_PTR_ARG(1);
+
+ /** Sends a byte to the currently addressed device on the TWI bus.
+ *
+ * \param[in] twi The TWI Peripheral to use
+ * \param[in] Byte Byte to send to the currently addressed device
+ *
+ * \return Boolean \c true if the recipient ACKed the byte, \c false otherwise
+ */
+ bool TWI_SendByte(TWI_t *twi, const uint8_t Byte) ATTR_NON_NULL_PTR_ARG(1);
+
+ /** Receives a byte from the currently addressed device on the TWI bus.
+ *
+ * \param[in] twi The TWI Peripheral to use
+ * \param[in] Byte Location where the read byte is to be stored.
+ * \param[in] LastByte Indicates if the byte should be ACKed if false, NAKed if true.
+ *
+ * \return Boolean \c true if the byte reception successfully completed, \c false otherwise.
+ */
+ bool TWI_ReceiveByte(TWI_t *twi, uint8_t* const Byte,
+ const bool LastByte) ATTR_NON_NULL_PTR_ARG(1, 2);
+
+ /** High level function to perform a complete packet transfer over the TWI bus to the specified
+ * device.
+ *
+ * \param[in] twi The TWI Peripheral to use
+ * \param[in] SlaveAddress Base address of the TWI slave device to communicate with.
+ * \param[in] TimeoutMS Timeout for bus capture and slave START ACK, in milliseconds.
+ * \param[in] InternalAddress Pointer to a location where the internal slave read start address is stored.
+ * \param[in] InternalAddressLen Size of the internal device address, in bytes.
+ * \param[in] Buffer Pointer to a buffer where the read packet data is to be stored.
+ * \param[in] Length Size of the packet to read, in bytes.
+ *
+ * \return A value from the \ref TWI_ErrorCodes_t enum.
+ */
+ uint8_t TWI_ReadPacket(TWI_t *twi,
+ const uint8_t SlaveAddress,
+ const uint8_t TimeoutMS,
+ const uint8_t* InternalAddress,
+ uint8_t InternalAddressLen,
+ uint8_t* Buffer,
+ uint8_t Length) ATTR_NON_NULL_PTR_ARG(1, 4);
+
+ /** High level function to perform a complete packet transfer over the TWI bus from the specified
+ * device.
+ *
+ * \param[in] twi The TWI Peripheral to use
+ * \param[in] SlaveAddress Base address of the TWI slave device to communicate with
+ * \param[in] TimeoutMS Timeout for bus capture and slave START ACK, in milliseconds
+ * \param[in] InternalAddress Pointer to a location where the internal slave write start address is stored
+ * \param[in] InternalAddressLen Size of the internal device address, in bytes
+ * \param[in] Buffer Pointer to a buffer where the packet data to send is stored
+ * \param[in] Length Size of the packet to send, in bytes
+ *
+ * \return A value from the \ref TWI_ErrorCodes_t enum.
+ */
+ uint8_t TWI_WritePacket(TWI_t *twi,
+ const uint8_t SlaveAddress,
+ const uint8_t TimeoutMS,
+ const uint8_t* InternalAddress,
+ uint8_t InternalAddressLen,
+ const uint8_t* Buffer,
+ uint8_t Length) ATTR_NON_NULL_PTR_ARG(1, 4);
+
+ /* Disable C linkage for C++ Compilers: */
+ #if defined(__cplusplus)
+ }
+ #endif
+
+#endif
+
+/** @} */
+