1 files changed, 54 insertions, 0 deletions
diff --git a/LUFA/Drivers/Peripheral/TWI.c b/LUFA/Drivers/Peripheral/TWI.c
new file mode 100644
index 000000000..6028bbae9
--- /dev/null
+++ b/LUFA/Drivers/Peripheral/TWI.c
@@ -0,0 +1,54 @@
+/*
+     Copyright (C) Dean Camera, 2010.
+              
+  dean [at] fourwalledcubicle [dot] com
+      www.fourwalledcubicle.com
+*/
+
+#include "TWI.h"
+
+bool TWI_StartTransmission(uint8_t SlaveAddress)
+{
+	for (;;)
+	{
+		uint8_t IterationsRemaining = 50;
+		bool    BusCaptured = false;
+
+		while (IterationsRemaining-- && !BusCaptured)
+		{
+			TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN));	
+			while (!(TWCR & (1 << TWINT)));
+				
+			switch (TWSR & TW_STATUS_MASK)
+			{
+				case TW_START:
+				case TW_REP_START:
+					BusCaptured = true;
+					break;
+				case TW_MT_ARB_LOST:
+					continue;
+				default:
+					return false;
+			}
+		}
+		
+		if (!(BusCaptured))
+		  return false;
+		  
+		TWDR = SlaveAddress;
+		TWCR = ((1 << TWINT) | (1 << TWEN));
+		while (!(TWCR & (1 << TWINT)));
+		
+		GPIOR0 = (TWSR & TW_STATUS_MASK);
+
+		switch (TWSR & TW_STATUS_MASK)
+		{
+			case TW_MT_SLA_ACK:
+			case TW_MR_SLA_ACK:
+				return true;
+			default:
+				TWI_StopTransmission();
+				break;
+		}		  
+	}
+}