X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/8de31cbb78f98eb4d3c5b7232e85337b15f294e5..e39f3378a21ae5076e8c49bc728c20e436e3a69f:/Projects/XPLAINBridge/Lib/SoftUART.c

diff --git a/Projects/XPLAINBridge/Lib/SoftUART.c b/Projects/XPLAINBridge/Lib/SoftUART.c
index 4ec8dcdc8..152c4e187 100644
--- a/Projects/XPLAINBridge/Lib/SoftUART.c
+++ b/Projects/XPLAINBridge/Lib/SoftUART.c
@@ -1,23 +1,23 @@
 /*
-			 LUFA Library
-	 Copyright (C) Dean Camera, 2010.
-			  
+             LUFA Library
+     Copyright (C) Dean Camera, 2012.
+
   dean [at] fourwalledcubicle [dot] com
-	  www.fourwalledcubicle.com
+           www.lufa-lib.org
 */
 
 /*
   Copyright 2010  David Prentice (david.prentice [at] farming [dot] uk)
   Copyright 2010  Peter Danneger
-  Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)
+  Copyright 2012  Dean Camera (dean [at] fourwalledcubicle [dot] com)
 
-  Permission to use, copy, modify, distribute, and sell this 
+  Permission to use, copy, modify, distribute, and sell this
   software and its documentation for any purpose is hereby granted
-  without fee, provided that the above copyright notice appear in 
+  without fee, provided that the above copyright notice appear in
   all copies and that both that the copyright notice and this
-  permission notice and warranty disclaimer appear in supporting 
-  documentation, and that the name of the author not be used in 
-  advertising or publicity pertaining to distribution of the 
+  permission notice and warranty disclaimer appear in supporting
+  documentation, and that the name of the author not be used in
+  advertising or publicity pertaining to distribution of the
   software without specific, written prior permission.
 
   The author disclaim all warranties with regard to this
@@ -51,6 +51,7 @@ static uint8_t RX_BitsRemaining;
 /** Temporary data variable to hold the byte being received as it is shifted in */
 static uint8_t RX_Data;
 
+
 /** Initializes the software UART, ready for data transmission and reception into the global ring buffers. */
 void SoftUART_Init(void)
 {
@@ -63,12 +64,13 @@ void SoftUART_Init(void)
 	EICRA  = (1 << ISC01);
 	EIMSK  = (1 << INT0);
 
-	/* Set reception timer compare period and enable compare ISR */
-	OCR1A  = BIT_TIME;
+	/* Set the transmission and reception timer compare values for the default baud rate */
+	SoftUART_SetBaud(9600);
+
+	/* Setup reception timer compare ISR */
 	TIMSK1 = (1 << OCIE1A);
 
-	/* Set transmission timer compare period, enable compare ISR and start the timer */
-	OCR3A  = BIT_TIME;
+	/* Setup transmission timer compare ISR and start the timer */
 	TIMSK3 = (1 << OCIE3A);
 	TCCR3B = ((1 << CS30) | (1 << WGM32));
 }
@@ -78,9 +80,11 @@ ISR(INT0_vect, ISR_BLOCK)
 {
 	/* Reset the number of reception bits remaining counter */
 	RX_BitsRemaining = 8;
-	
-	/* Reset the bit reception timer */
-	TCNT1 = 0;
+
+	/* Reset the bit reception timer to -(1/2) of the total bit time, so that the first data bit is
+	 * sampled mid way through the total bit time, making reception more robust.
+	 */
+	TCNT1 = -(OCR1A >> 1);
 
 	/* Check to see that the pin is still low (prevents glitches from starting a frame reception) */
 	if (!(SRXPIN & (1 << SRX)))
@@ -119,7 +123,7 @@ ISR(TIMER1_COMPA_vect, ISR_BLOCK)
 
 		/* Reception complete, store the received byte if stop bit valid */
 		if (SRX_Cached)
-		  RingBuffer_Insert(&UARTtoUSB_Buffer, RX_Data);	
+		  RingBuffer_Insert(&UARTtoUSB_Buffer, RX_Data);
 	}
 }
 
@@ -139,7 +143,7 @@ ISR(TIMER3_COMPA_vect, ISR_BLOCK)
 		TX_Data >>= 1;
 		TX_BitsRemaining--;
 	}
-	else if (USBtoUART_Buffer.Count && !(RX_BitsRemaining))
+	else if (!(RX_BitsRemaining) && !(RingBuffer_IsEmpty(&USBtoUART_Buffer)))
 	{
 		/* Start bit - TX line low */
 		STXPORT &= ~(1 << STX);
@@ -149,3 +153,4 @@ ISR(TIMER3_COMPA_vect, ISR_BLOCK)
 		TX_BitsRemaining = 9;
 	}
 }
+