/* 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
#if !(defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB646__) || \
defined(__AVR_AT90USB1287__) || defined(__AVR_AT90USB647__) || \
defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
#error The TWI peripheral driver is not currently available for your selected microcontroller model.
#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
/** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 1. */
#define TWI_BIT_PRESCALE_1 ((0 << TWPS1) | (0 << TWPS0))
/** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 4. */
#define TWI_BIT_PRESCALE_4 ((0 << TWPS1) | (1 << TWPS0))
/** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 16. */
#define TWI_BIT_PRESCALE_16 ((1 << TWPS1) | (0 << TWPS0))
/** Bit length prescaler for \ref TWI_Init(). This mask multiplies the TWI bit length prescaler by 64. */
#define TWI_BIT_PRESCALE_64 ((1 << TWPS1) | (1 << TWPS0))
/** 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] Prescale Prescaler set on the TWI bus.
* \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_BITLENGTH_FROM_FREQ(Prescale, Frequency) ((((F_CPU / (Prescale)) / (Frequency)) - 16) / 2)
/* 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 / (16 + 2 * BitLength + 4 ^ Prescale)
.
*
* \attention The value of the \c BitLength parameter should not be set below 10 or invalid bus conditions may
* occur, as indicated in the AVR8 microcontroller datasheet.
*
* \param[in] Prescale Prescaler to use when determining the bus frequency, a \c TWI_BIT_PRESCALE_* value.
* \param[in] BitLength Length of the bits sent on the bus.
*/
static inline void TWI_Init(const uint8_t Prescale,
const uint8_t BitLength) ATTR_ALWAYS_INLINE;
static inline void TWI_Init(const uint8_t Prescale,
const uint8_t BitLength)
{
TWCR |= (1 << TWEN);
TWSR = Prescale;
TWBR = BitLength;
}
/** 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.
*/
static inline void TWI_Disable(void) ATTR_ALWAYS_INLINE;
static inline void TWI_Disable(void)
{
TWCR &= ~(1 << TWEN);
}
/** Sends a TWI STOP onto the TWI bus, terminating communication with the currently addressed device. */
static inline void TWI_StopTransmission(void) ATTR_ALWAYS_INLINE;
static inline void TWI_StopTransmission(void)
{
TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
}
/* Function Prototypes: */
/** Begins a master mode TWI bus communication with the given slave device address.
*
* \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(const uint8_t SlaveAddress,
const uint8_t TimeoutMS);
/** Sends a byte to the currently addressed device on the TWI bus.
*
* \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(const uint8_t Byte);
/** Receives a byte from the currently addressed device on the TWI bus.
*
* \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(uint8_t* const Byte,
const bool LastByte) ATTR_NON_NULL_PTR_ARG(1);
/** High level function to perform a complete packet transfer over the TWI bus to the specified
* device.
*
* \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(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(3);
/** High level function to perform a complete packet transfer over the TWI bus from the specified
* device.
*
* \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(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(3);
/* Disable C linkage for C++ Compilers: */
#if defined(__cplusplus)
}
#endif
#endif
/** @} */