From 237ea87c4fcb4865863fc15e07e179323caa7881 Mon Sep 17 00:00:00 2001
From: Håvard Espeland <gus@ping.uio.no>
Date: Sat, 5 Feb 2011 19:26:39 +0100
Subject: Fork of LUFA CDC Bootloader Initial commit

---
 LUFA/Drivers/Peripheral/TWI.c | 75 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 LUFA/Drivers/Peripheral/TWI.c

(limited to 'LUFA/Drivers/Peripheral/TWI.c')

diff --git a/LUFA/Drivers/Peripheral/TWI.c b/LUFA/Drivers/Peripheral/TWI.c
new file mode 100644
index 0000000..4694b0b
--- /dev/null
+++ b/LUFA/Drivers/Peripheral/TWI.c
@@ -0,0 +1,75 @@
+/*
+     Copyright (C) Dean Camera, 2010.
+
+  dean [at] fourwalledcubicle [dot] com
+           www.lufa-lib.org
+*/
+
+#include "TWI.h"
+
+bool TWI_StartTransmission(const uint8_t SlaveAddress,
+                           const uint8_t TimeoutMS)
+{
+	for (;;)
+	{
+		bool     BusCaptured = false;
+		uint16_t TimeoutRemaining;
+
+		TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN));
+
+		TimeoutRemaining = (TimeoutMS * 100);
+		while (TimeoutRemaining-- && !(BusCaptured))
+		{
+			if (TWCR & (1 << TWINT))
+			{
+				switch (TWSR & TW_STATUS_MASK)
+				{
+					case TW_START:
+					case TW_REP_START:
+						BusCaptured = true;
+						break;
+					case TW_MT_ARB_LOST:
+						TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN));
+						continue;
+					default:
+						TWCR = (1 << TWEN);
+						return false;
+				}
+			}
+
+			_delay_us(10);
+		}
+
+		if (!(BusCaptured))
+		{
+			TWCR = (1 << TWEN);
+			return false;
+		}
+
+		TWDR = SlaveAddress;
+		TWCR = ((1 << TWINT) | (1 << TWEN));
+
+		TimeoutRemaining = (TimeoutMS * 100);
+		while (TimeoutRemaining--)
+		{
+			if (TWCR & (1 << TWINT))
+			  break;
+
+			_delay_us(10);
+		}
+
+		if (!(TimeoutRemaining))
+		  return false;
+
+		switch (TWSR & TW_STATUS_MASK)
+		{
+			case TW_MT_SLA_ACK:
+			case TW_MR_SLA_ACK:
+				return true;
+			default:
+				TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
+				return false;
+		}
+	}
+}
+
-- 
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