Remove non-functional maintenance link check.

[pub/USBasp.git] / Projects / XPLAINBridge / Lib / SoftUART.c

diff --git a/Projects/XPLAINBridge/Lib/SoftUART.c b/Projects/XPLAINBridge/Lib/SoftUART.c
index 8710722..152c4e1 100644 (file)
--- 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)
 {
@@ -79,9 +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)))
@@ -120,7 +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);
        }
 }
 
@@ -140,7 +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);
@@ -150,3 +153,4 @@ ISR(TIMER3_COMPA_vect, ISR_BLOCK)
                TX_BitsRemaining = 9;
        }
 }
+