X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/229935184b3ca7eda9edd6b7d7851f53b2441a65..3642ea0b9715cdf0196b10c9fc97898940eaefa6:/Projects/XPLAINBridge/Lib/SoftUART.c?ds=inline

diff --git a/Projects/XPLAINBridge/Lib/SoftUART.c b/Projects/XPLAINBridge/Lib/SoftUART.c
index 458a505cd..f71686fe1 100644
--- a/Projects/XPLAINBridge/Lib/SoftUART.c
+++ b/Projects/XPLAINBridge/Lib/SoftUART.c
@@ -1,26 +1,26 @@
 /*
-			 LUFA Library
-	 Copyright (C) Dean Camera, 2010.
-			  
+             LUFA Library
+     Copyright (C) Dean Camera, 2015.
+
   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 2015  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
+  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
@@ -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));
 }
@@ -76,15 +78,23 @@ void SoftUART_Init(void)
 /** ISR to detect the start of a bit being sent to the software UART. */
 ISR(INT0_vect, ISR_BLOCK)
 {
-	/* Reset and start the reception timer */
-	TCNT1  = 0;
-	TCCR1B = ((1 << CS10) | (1 << WGM12));
-
 	/* Reset the number of reception bits remaining counter */
 	RX_BitsRemaining = 8;
 
-	/* Disable start bit detection ISR while the next byte is received */
-	EIMSK = 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)))
+	{
+		/* Disable start bit detection ISR while the next byte is received */
+		EIMSK = 0;
+
+		/* Start the reception timer */
+		TCCR1B = ((1 << CS10) | (1 << WGM12));
+	}
 }
 
 /** ISR to manage the reception of bits to the software UART. */
@@ -113,12 +123,12 @@ 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);
 	}
 }
 
 /** ISR to manage the transmission of bits via the software UART. */
-ISR(TIMER3_COMPA_vect, ISR_NOBLOCK)
+ISR(TIMER3_COMPA_vect, ISR_BLOCK)
 {
 	/* Check if transmission has finished */
 	if (TX_BitsRemaining)
@@ -133,7 +143,7 @@ ISR(TIMER3_COMPA_vect, ISR_NOBLOCK)
 		TX_Data >>= 1;
 		TX_BitsRemaining--;
 	}
-	else if (USBtoUART_Buffer.Count)
+	else if (!(RX_BitsRemaining) && !(RingBuffer_IsEmpty(&USBtoUART_Buffer)))
 	{
 		/* Start bit - TX line low */
 		STXPORT &= ~(1 << STX);
@@ -143,3 +153,4 @@ ISR(TIMER3_COMPA_vect, ISR_NOBLOCK)
 		TX_BitsRemaining = 9;
 	}
 }
+