X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/bad956bace05c603e9d6e63718f40ae173f5052f..7cd9e0dbc45afa4b047711d5dc255f4850e80c6b:/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c

diff --git a/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c b/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c
index 2f65921ca..e7629d5b7 100644
--- a/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c
+++ b/LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c
@@ -1,13 +1,13 @@
 /*
              LUFA Library
-     Copyright (C) Dean Camera, 2011.
+     Copyright (C) Dean Camera, 2013.
 
   dean [at] fourwalledcubicle [dot] com
            www.lufa-lib.org
 */
 
 /*
-  Copyright 2011  Dean Camera (dean [at] fourwalledcubicle [dot] com)
+  Copyright 2013  Dean Camera (dean [at] fourwalledcubicle [dot] com)
 
   Permission to use, copy, modify, distribute, and sell this
   software and its documentation for any purpose is hereby granted
@@ -18,7 +18,7 @@
   advertising or publicity pertaining to distribution of the
   software without specific, written prior permission.
 
-  The author disclaim all warranties with regard to this
+  The author disclaims all warranties with regard to this
   software, including all implied warranties of merchantability
   and fitness.  In no event shall the author be liable for any
   special, indirect or consequential damages or any damages
@@ -28,6 +28,9 @@
   this software.
 */
 
+#include "../../../Common/Common.h"
+#if (ARCH == ARCH_AVR8) && defined(TWCR)
+
 #define  __INCLUDE_FROM_TWI_C
 #include "../TWI.h"
 
@@ -42,7 +45,7 @@ uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
 		TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN));
 
 		TimeoutRemaining = (TimeoutMS * 100);
-		while (TimeoutRemaining-- && !(BusCaptured))
+		while (TimeoutRemaining && !(BusCaptured))
 		{
 			if (TWCR & (1 << TWINT))
 			{
@@ -62,6 +65,7 @@ uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
 			}
 
 			_delay_us(10);
+			TimeoutRemaining--;
 		}
 
 		if (!(TimeoutRemaining))
@@ -74,12 +78,13 @@ uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
 		TWCR = ((1 << TWINT) | (1 << TWEN));
 
 		TimeoutRemaining = (TimeoutMS * 100);
-		while (TimeoutRemaining--)
+		while (TimeoutRemaining)
 		{
 			if (TWCR & (1 << TWINT))
 			  break;
 
 			_delay_us(10);
+			TimeoutRemaining--;
 		}
 
 		if (!(TimeoutRemaining))
@@ -97,36 +102,71 @@ 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,
-                       const uint8_t InternalAddressLen,
+                       uint8_t InternalAddressLen,
                        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 == 0))))
+			if (!(TWI_SendByte(*(InternalAddress++))))
 			{
 				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;
 }
 
@@ -159,9 +199,11 @@ uint8_t TWI_WritePacket(const uint8_t SlaveAddress,
 				break;
 			}
 		}
-		
+
 		TWI_StopTransmission();
 	}
-	
+
 	return ErrorCode;
 }
+
+#endif