#define __INCLUDE_FROM_TWI_C
#include "../TWI.h"
-static inline bool bitmask_is_set(uint8_t byte, uint8_t mask) {
- return (byte & mask) == mask;
-}
-
-uint8_t TWI_StartTransmission(TWI_t *twi,
+uint8_t TWI_StartTransmission(TWI_t* const TWI,
const uint8_t SlaveAddress,
const uint8_t TimeoutMS)
{
- uint16_t TimeoutRemaining;
-
- twi->MASTER.ADDR = SlaveAddress;
-
- TimeoutRemaining = (TimeoutMS * 100);
- while (TimeoutRemaining)
- {
- uint8_t status = twi->MASTER.STATUS;
- if (bitmask_is_set(status, TWI_MASTER_WIF_bm | TWI_MASTER_ARBLOST_bm))
- {
- // Case 1: Arbitration lost. Try again. (or error)
- twi->MASTER.ADDR = SlaveAddress;
- }
- else if (bitmask_is_set(status, TWI_MASTER_WIF_bm | TWI_MASTER_RXACK_bm))
- {
- // Case 2: No response from slave.
- // We need to release the bus.
- TWI_StopTransmission(twi);
- return TWI_ERROR_SlaveResponseTimeout;
- }
- else if (status & TWI_MASTER_WIF_bm)
- {
- // Case 3: Slave ACK the Write. Ready!
- return TWI_ERROR_NoError;
- }
- else if (status & TWI_MASTER_RIF_bm)
- {
- // Case 4: Slave ACK the Read. Ready! (a byte will be read)
- return TWI_ERROR_NoError;
- }
- // Still waiting..
- _delay_us(10);
- TimeoutRemaining--;
- }
-
- if (!(TimeoutRemaining)) {
- if (twi->MASTER.STATUS & TWI_MASTER_CLKHOLD_bm) {
- // Release the bus if we're holding it.
- TWI_StopTransmission(twi);
- }
- }
- return TWI_ERROR_BusCaptureTimeout;
+ uint16_t TimeoutRemaining;
+
+ TWI->MASTER.ADDR = SlaveAddress;
+
+ TimeoutRemaining = (TimeoutMS * 100);
+ while (TimeoutRemaining)
+ {
+ uint8_t status = TWI->MASTER.STATUS;
+
+ if ((status & (TWI_MASTER_WIF_bm | TWI_MASTER_ARBLOST_bm)) == (TWI_MASTER_WIF_bm | TWI_MASTER_ARBLOST_bm))
+ {
+ TWI->MASTER.ADDR = SlaveAddress;
+ }
+ else if ((status & (TWI_MASTER_WIF_bm | TWI_MASTER_RXACK_bm)) == (TWI_MASTER_WIF_bm | TWI_MASTER_RXACK_bm))
+ {
+ TWI_StopTransmission(twi);
+ return TWI_ERROR_SlaveResponseTimeout;
+ }
+ else if (status & (TWI_MASTER_WIF_bm | TWI_MASTER_RIF_bm))
+ {
+ return TWI_ERROR_NoError;
+ }
+
+ _delay_us(10);
+ TimeoutRemaining--;
+ }
+
+ if (!(TimeoutRemaining)) {
+ if (TWI->MASTER.STATUS & TWI_MASTER_CLKHOLD_bm) {
+ TWI_StopTransmission(twi);
+ }
+ }
+
+ return TWI_ERROR_BusCaptureTimeout;
}
-bool TWI_SendByte(TWI_t *twi, const uint8_t Byte)
+bool TWI_SendByte(TWI_t* const TWI,
+ const uint8_t Byte)
{
- // We assume we're ready to write!
- twi->MASTER.DATA = Byte;
- while (!(twi->MASTER.STATUS & TWI_MASTER_WIF_bm));
- return (twi->MASTER.STATUS & TWI_MASTER_WIF_bm) && !(twi->MASTER.STATUS & TWI_MASTER_RXACK_bm);
+ TWI->MASTER.DATA = Byte;
+
+ while (!(TWI->MASTER.STATUS & TWI_MASTER_WIF_bm));
+
+ return (TWI->MASTER.STATUS & TWI_MASTER_WIF_bm) && !(TWI->MASTER.STATUS & TWI_MASTER_RXACK_bm);
}
-bool TWI_ReceiveByte(TWI_t *twi, uint8_t* const Byte,
- const bool LastByte)
+bool TWI_ReceiveByte(TWI_t* const TWI,
+ uint8_t* const Byte,
+ const bool LastByte)
{
- // If we're here, we should already be reading. Wait if we haven't read yet.
- if (bitmask_is_set(twi->MASTER.STATUS, TWI_MASTER_BUSERR_bm | TWI_MASTER_ARBLOST_bm)) {
- return false;
- }
- while (!(twi->MASTER.STATUS & TWI_MASTER_RIF_bm));
- *Byte = twi->MASTER.DATA;
- if (LastByte)
- twi->MASTER.CTRLC = TWI_MASTER_ACKACT_bm | TWI_MASTER_CMD_STOP_gc;
- else
- twi->MASTER.CTRLC = TWI_MASTER_CMD_RECVTRANS_gc;
- return true;
+ if ((TWI->MASTER.STATUS & (TWI_MASTER_BUSERR_bm | TWI_MASTER_ARBLOST_bm)) == (TWI_MASTER_BUSERR_bm | TWI_MASTER_ARBLOST_bm)) {
+ return false;
+ }
+
+ while (!(TWI->MASTER.STATUS & TWI_MASTER_RIF_bm));
+
+ *Byte = TWI->MASTER.DATA;
+
+ if (LastByte)
+ TWI->MASTER.CTRLC = TWI_MASTER_ACKACT_bm | TWI_MASTER_CMD_STOP_gc;
+ else
+ TWI->MASTER.CTRLC = TWI_MASTER_CMD_RECVTRANS_gc;
+
+ return true;
}
-uint8_t TWI_ReadPacket(TWI_t *twi,
+uint8_t TWI_ReadPacket(TWI_t* const TWI,
const uint8_t SlaveAddress,
const uint8_t TimeoutMS,
const uint8_t* InternalAddress,
}
if ((ErrorCode = TWI_StartTransmission(twi, (SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_READ,
- TimeoutMS)) == TWI_ERROR_NoError)
+ TimeoutMS)) == TWI_ERROR_NoError)
{
while (Length--)
{
break;
}
}
-
}
- TWI_StopTransmission(twi);
+
+ TWI_StopTransmission(twi);
}
return ErrorCode;
}
-uint8_t TWI_WritePacket(TWI_t *twi,
+uint8_t TWI_WritePacket(TWI_t* const twi,
const uint8_t SlaveAddress,
const uint8_t TimeoutMS,
const uint8_t* InternalAddress,
uint8_t Length)
{
uint8_t ErrorCode;
+
if ((ErrorCode = TWI_StartTransmission(twi, (SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE,
TimeoutMS)) == TWI_ERROR_NoError)
{
* \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.
+ * \param[in] TWI Pointer to the base of the TWI peripheral within the device.
+ * \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)
+ static inline void TWI_Init(TWI_t* const TWI,
+ const uint8_t Baud) ATTR_ALWAYS_INLINE ATTR_NON_NULL_PTR_ARG(1);
+ static inline void TWI_Init(TWI_t* const 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;
+ 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
+ *
+ * \param[in] TWI Pointer to the base of the TWI peripheral within the device.
*/
- 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)
+ static inline void TWI_Disable(TWI_t* const TWI) ATTR_ALWAYS_INLINE ATTR_NON_NULL_PTR_ARG(1);
+ static inline void TWI_Disable(TWI_t* const TWI)
{
- twi->MASTER.CTRLA &= ~TWI_MASTER_ENABLE_bm;
+ 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)
+ /** Sends a TWI STOP onto the TWI bus, terminating communication with the currently addressed device.
+ *
+ * \param[in] TWI Pointer to the base of the TWI peripheral within the device.
+ */
+ static inline void TWI_StopTransmission(TWI_t* const TWI) ATTR_ALWAYS_INLINE ATTR_NON_NULL_PTR_ARG(1);
+ static inline void TWI_StopTransmission(TWI_t* const TWI)
{
- twi->MASTER.CTRLC = TWI_MASTER_ACKACT_bm | TWI_MASTER_CMD_STOP_gc;
+ 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] TWI Pointer to the base of the TWI peripheral within the device.
* \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,
+ uint8_t TWI_StartTransmission(TWI_t* const 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] TWI Pointer to the base of the TWI peripheral within the device.
* \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);
+ bool TWI_SendByte(TWI_t* const 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] TWI Pointer to the base of the TWI peripheral within the device.
* \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,
+ bool TWI_ReceiveByte(TWI_t* const 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] TWI Pointer to the base of the TWI peripheral within the 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.
*
* \return A value from the \ref TWI_ErrorCodes_t enum.
*/
- uint8_t TWI_ReadPacket(TWI_t *twi,
- const uint8_t SlaveAddress,
+ uint8_t TWI_ReadPacket(TWI_t* const TWI,
+ const uint8_t SlaveAddress,
const uint8_t TimeoutMS,
const uint8_t* InternalAddress,
uint8_t InternalAddressLen,
/** 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] TWI Pointer to the base of the TWI peripheral within the 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
*
* \return A value from the \ref TWI_ErrorCodes_t enum.
*/
- uint8_t TWI_WritePacket(TWI_t *twi,
- const uint8_t SlaveAddress,
+ uint8_t TWI_WritePacket(TWI_t* const TWI,
+ const uint8_t SlaveAddress,
const uint8_t TimeoutMS,
const uint8_t* InternalAddress,
uint8_t InternalAddressLen,
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