Make TWI_ReadPacket() use a repeated start condition rather than a full bus release...

Fix TWI_ReadPacket() not releasing the bus correctly after all data transferred.

Make TWI_SendByte() and TWI_ReceiveByte() non-inline to reduce compiled binary size.

diff --git a/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c b/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c
index d4f594f..d6db37d 100644 (file)
--- a/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c
+++ b/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c
@@ -97,34 +97,69 @@ uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
        }
 }
 
        }
 }
 

+bool TWI_SendByte(const uint8_t Byte)
+{
+       TWDR = Byte;
+       TWCR = ((1 << TWINT) | (1 << TWEN));
+       while (!(TWCR & (1 << TWINT)));
+
+       return ((TWSR & TW_STATUS_MASK) == TW_MT_DATA_ACK);
+}
+
+bool TWI_ReceiveByte(uint8_t* const Byte,
+                                        const bool LastByte)
+{
+       uint8_t TWCRMask;
+
+       if (LastByte)
+         TWCRMask = ((1 << TWINT) | (1 << TWEN));
+       else
+         TWCRMask = ((1 << TWINT) | (1 << TWEN) | (1 << TWEA));
+
+       TWCR = TWCRMask;
+       while (!(TWCR & (1 << TWINT)));
+       *Byte = TWDR;
+       
+       uint8_t Status = (TWSR & TW_STATUS_MASK);
+       
+       return ((LastByte) ? (Status == TW_MR_DATA_NACK) : (Status == TW_MR_DATA_ACK));
+}
+

 uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
                        const uint8_t TimeoutMS,
                        const uint8_t* InternalAddress,
 uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
                        const uint8_t TimeoutMS,
                        const uint8_t* InternalAddress,

-                       const uint8_t InternalAddressLen,
+                       uint8_t InternalAddressLen,

                        uint8_t* Buffer,
                        uint8_t Length)
 {
        uint8_t ErrorCode;
        
                        uint8_t* Buffer,
                        uint8_t Length)
 {
        uint8_t ErrorCode;
        

-       if ((ErrorCode = TWI_WritePacket(SlaveAddress, TimeoutMS, InternalAddress, InternalAddressLen,
-                                        NULL, 0)) != TWI_ERROR_NoError)
-       {
-               return ErrorCode;
-       }
-
-       if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_READ,
-                                                                                  TimeoutMS)) == TWI_ERROR_NoError)
+       if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE,
+                                              TimeoutMS)) == TWI_ERROR_NoError)

        {
        {

-               while (Length--)
+               while (InternalAddressLen--)

                {
                {

-                       if (!(TWI_ReceiveByte(Buffer++, (Length == 1))))
-                       {
+                       if (!(TWI_SendByte(*(InternalAddress++))))
+                       {                               

                                ErrorCode = TWI_ERROR_SlaveNAK;
                                break;
                        }
                }
                
                                ErrorCode = TWI_ERROR_SlaveNAK;
                                break;
                        }
                }
                

-               TWI_StopTransmission();
+               if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_READ,
+                                                                                          TimeoutMS)) == TWI_ERROR_NoError)
+               {
+                       while (Length--)
+                       {
+                               if (!(TWI_ReceiveByte(Buffer++, (Length == 0))))
+                               {
+                                       ErrorCode = TWI_ERROR_SlaveNAK;
+                                       break;
+                               }
+                       }
+                       
+                       TWI_StopTransmission();
+               }

        }
        
        return ErrorCode;
        }
        
        return ErrorCode;


@@ -145,7 +180,7 @@ uint8_t TWI_WritePacket(const uint8_t SlaveAddress,
                while (InternalAddressLen--)
                {
                        if (!(TWI_SendByte(*(InternalAddress++))))
                while (InternalAddressLen--)
                {
                        if (!(TWI_SendByte(*(InternalAddress++))))

-                       {
+                       {                               

                                ErrorCode = TWI_ERROR_SlaveNAK;
                                break;
                        }
                                ErrorCode = TWI_ERROR_SlaveNAK;
                                break;
                        }

diff --git a/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.h b/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.h
index 63b9f03..705ef53 100644 (file)
--- a/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.h
+++ b/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.h
@@ -99,14 +99,14 @@
  *      uint8_t WritePacket[3] = {0x01, 0x02, 0x03};
  *
  *      TWI_WritePacket(0xA0, 10, &InternalWriteAddress, sizeof(InternalWriteAddress),
  *      uint8_t WritePacket[3] = {0x01, 0x02, 0x03};
  *
  *      TWI_WritePacket(0xA0, 10, &InternalWriteAddress, sizeof(InternalWriteAddress),

- *                      WritePacket, sizeof(WritePacket);
+ *                      &WritePacket, sizeof(WritePacket);

  *
  *      // Start a read session to device at address 0xA0, internal address 0xDC with a 10ms timeout
  *      uint8_t InternalReadAddress = 0xDC;
  *      uint8_t ReadPacket[3];
  *
  *      TWI_ReadPacket(0xA0, 10, &InternalReadAddress, sizeof(InternalReadAddress),
  *
  *      // Start a read session to device at address 0xA0, internal address 0xDC with a 10ms timeout
  *      uint8_t InternalReadAddress = 0xDC;
  *      uint8_t ReadPacket[3];
  *
  *      TWI_ReadPacket(0xA0, 10, &InternalReadAddress, sizeof(InternalReadAddress),

- *                     ReadPacket, sizeof(ReadPacket);
+ *                     &ReadPacket, sizeof(ReadPacket);

  *  \endcode
  *
  *  @{
  *  \endcode
  *
  *  @{


@@ -215,20 +215,24 @@
                                TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
                        }
 
                                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
                         */
                        /** 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
                         */

-                       static inline bool TWI_SendByte(const uint8_t Byte)
-                       {
-                               TWDR = Byte;
-                               TWCR = ((1 << TWINT) | (1 << TWEN));
-                               while (!(TWCR & (1 << TWINT)));
-
-                               return ((TWSR & TW_STATUS_MASK) == TW_MT_DATA_ACK);
-                       }
+                       bool TWI_SendByte(const uint8_t Byte);

 
                        /** Receives a byte from the currently addressed device on the TWI bus.
                         *
 
                        /** Receives a byte from the currently addressed device on the TWI bus.
                         *


@@ -237,32 +241,11 @@
                         *
                         *  \return Boolean \c true if the byte reception successfully completed, \c false otherwise.
                         */
                         *
                         *  \return Boolean \c true if the byte reception successfully completed, \c false otherwise.
                         */

-                       static inline bool TWI_ReceiveByte(uint8_t* const Byte,
-                                                          const bool LastByte)
-                       {
-                               uint8_t TWCRMask = ((1 << TWINT) | (1 << TWEN));
-
-                               if (!(LastByte))
-                                 TWCRMask |= (1 << TWEA);
-
-                               TWCR = TWCRMask;
-                               while (!(TWCR & (1 << TWINT)));
-                               *Byte = TWDR;
-
-                               return ((TWSR & TW_STATUS_MASK) == TW_MR_DATA_ACK);
-                       }
-
-               /* 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);
-
+                       bool TWI_ReceiveByte(uint8_t* const Byte,
+                                            const bool LastByte) ATTR_NON_NULL_PTR_ARG(1);
+                       bool TWI_ReceiveByte(uint8_t* const Byte,
+                                            const bool LastByte);
+                                        

                        /** High level function to perform a complete packet transfer over the TWI bus to the specified
                         *  device.
                         *
                        /** High level function to perform a complete packet transfer over the TWI bus to the specified
                         *  device.
                         *


@@ -278,7 +261,7 @@
                        uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
                                               const uint8_t TimeoutMS,
                                               const uint8_t* InternalAddress,
                        uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
                                               const uint8_t TimeoutMS,
                                               const uint8_t* InternalAddress,

-                                              const uint8_t InternalAddressLen,
+                                              uint8_t InternalAddressLen,

                                               uint8_t* Buffer,
                                               uint8_t Length) ATTR_NON_NULL_PTR_ARG(3);
 
                                               uint8_t* Buffer,
                                               uint8_t Length) ATTR_NON_NULL_PTR_ARG(3);