Moving the processing-5503 branch (used for Arduino 0017) into the trunk.

1 files changed, 76 insertions, 48 deletions

diff --git a/cores/arduino/HardwareSerial.cpp b/cores/arduino/HardwareSerial.cpp
index f8a959a..1af6a66 100755
--- a/cores/arduino/HardwareSerial.cpp
+++ b/cores/arduino/HardwareSerial.cpp
@@ -49,41 +49,41 @@ ring_buffer rx_buffer3 = { { 0 }, 0, 0 };
 
 inline void store_char(unsigned char c, ring_buffer *rx_buffer)
 {
-	int i = (rx_buffer->head + 1) % RX_BUFFER_SIZE;
-
-	// if we should be storing the received character into the location
-	// just before the tail (meaning that the head would advance to the
-	// current location of the tail), we're about to overflow the buffer
-	// and so we don't write the character or advance the head.
-	if (i != rx_buffer->tail) {
-		rx_buffer->buffer[rx_buffer->head] = c;
-		rx_buffer->head = i;
-	}
+  int i = (rx_buffer->head + 1) % RX_BUFFER_SIZE;
+
+  // if we should be storing the received character into the location
+  // just before the tail (meaning that the head would advance to the
+  // current location of the tail), we're about to overflow the buffer
+  // and so we don't write the character or advance the head.
+  if (i != rx_buffer->tail) {
+    rx_buffer->buffer[rx_buffer->head] = c;
+    rx_buffer->head = i;
+  }
 }
 
 #if defined(__AVR_ATmega1280__)
 
 SIGNAL(SIG_USART0_RECV)
 {
-	unsigned char c = UDR0;
+  unsigned char c = UDR0;
   store_char(c, &rx_buffer);
 }
 
 SIGNAL(SIG_USART1_RECV)
 {
-	unsigned char c = UDR1;
+  unsigned char c = UDR1;
   store_char(c, &rx_buffer1);
 }
 
 SIGNAL(SIG_USART2_RECV)
 {
-	unsigned char c = UDR2;
+  unsigned char c = UDR2;
   store_char(c, &rx_buffer2);
 }
 
 SIGNAL(SIG_USART3_RECV)
 {
-	unsigned char c = UDR3;
+  unsigned char c = UDR3;
   store_char(c, &rx_buffer3);
 }
 
@@ -96,9 +96,9 @@ SIGNAL(USART_RX_vect)
 #endif
 {
 #if defined(__AVR_ATmega8__)
-	unsigned char c = UDR;
+  unsigned char c = UDR;
 #else
-	unsigned char c = UDR0;
+  unsigned char c = UDR0;
 #endif
   store_char(c, &rx_buffer);
 }
@@ -111,7 +111,7 @@ HardwareSerial::HardwareSerial(ring_buffer *rx_buffer,
   volatile uint8_t *ubrrh, volatile uint8_t *ubrrl,
   volatile uint8_t *ucsra, volatile uint8_t *ucsrb,
   volatile uint8_t *udr,
-  uint8_t rxen, uint8_t txen, uint8_t rxcie, uint8_t udre)
+  uint8_t rxen, uint8_t txen, uint8_t rxcie, uint8_t udre, uint8_t u2x)
 {
   _rx_buffer = rx_buffer;
   _ubrrh = ubrrh;
@@ -123,14 +123,43 @@ HardwareSerial::HardwareSerial(ring_buffer *rx_buffer,
   _txen = txen;
   _rxcie = rxcie;
   _udre = udre;
+  _u2x = u2x;
 }
 
 // Public Methods //////////////////////////////////////////////////////////////
 
-void HardwareSerial::begin(long speed)
+void HardwareSerial::begin(long baud)
 {
-	*_ubrrh = ((F_CPU / 16 + speed / 2) / speed - 1) >> 8;
-	*_ubrrl = ((F_CPU / 16 + speed / 2) / speed - 1);
+  uint16_t baud_setting;
+  bool use_u2x;
+
+  // U2X mode is needed for baud rates higher than (CPU Hz / 16)
+  if (baud > F_CPU / 16) {
+    use_u2x = true;
+  } else {
+    // figure out if U2X mode would allow for a better connection
+    
+    // calculate the percent difference between the baud-rate specified and
+    // the real baud rate for both U2X and non-U2X mode (0-255 error percent)
+    uint8_t nonu2x_baud_error = abs((int)(255-((F_CPU/(16*(((F_CPU/8/baud-1)/2)+1))*255)/baud)));
+    uint8_t u2x_baud_error = abs((int)(255-((F_CPU/(8*(((F_CPU/4/baud-1)/2)+1))*255)/baud)));
+    
+    // prefer non-U2X mode because it handles clock skew better
+    use_u2x = (nonu2x_baud_error > u2x_baud_error);
+  }
+  
+  if (use_u2x) {
+    *_ucsra = 1 << _u2x;
+    baud_setting = (F_CPU / 4 / baud - 1) / 2;
+  } else {
+    *_ucsra = 0;
+    baud_setting = (F_CPU / 8 / baud - 1) / 2;
+  }
+
+  // assign the baud_setting, a.k.a. ubbr (USART Baud Rate Register)
+  *_ubrrh = baud_setting >> 8;
+  *_ubrrl = baud_setting;
+
   sbi(*_ucsrb, _rxen);
   sbi(*_ucsrb, _txen);
   sbi(*_ucsrb, _rxcie);
@@ -138,54 +167,53 @@ void HardwareSerial::begin(long speed)
 
 uint8_t HardwareSerial::available(void)
 {
-	return (RX_BUFFER_SIZE + _rx_buffer->head - _rx_buffer->tail) % RX_BUFFER_SIZE;
+  return (RX_BUFFER_SIZE + _rx_buffer->head - _rx_buffer->tail) % RX_BUFFER_SIZE;
 }
 
 int HardwareSerial::read(void)
 {
-	// if the head isn't ahead of the tail, we don't have any characters
-	if (_rx_buffer->head == _rx_buffer->tail) {
-		return -1;
-	} else {
-		unsigned char c = _rx_buffer->buffer[_rx_buffer->tail];
-		_rx_buffer->tail = (_rx_buffer->tail + 1) % RX_BUFFER_SIZE;
-		return c;
-	}
+  // if the head isn't ahead of the tail, we don't have any characters
+  if (_rx_buffer->head == _rx_buffer->tail) {
+    return -1;
+  } else {
+    unsigned char c = _rx_buffer->buffer[_rx_buffer->tail];
+    _rx_buffer->tail = (_rx_buffer->tail + 1) % RX_BUFFER_SIZE;
+    return c;
+  }
 }
 
 void HardwareSerial::flush()
 {
-	// don't reverse this or there may be problems if the RX interrupt
-	// occurs after reading the value of rx_buffer_head but before writing
-	// the value to rx_buffer_tail; the previous value of rx_buffer_head
-	// may be written to rx_buffer_tail, making it appear as if the buffer
-	// don't reverse this or there may be problems if the RX interrupt
-	// occurs after reading the value of rx_buffer_head but before writing
-	// the value to rx_buffer_tail; the previous value of rx_buffer_head
-	// may be written to rx_buffer_tail, making it appear as if the buffer
-	// were full, not empty.
-	_rx_buffer->head = _rx_buffer->tail;
+  // don't reverse this or there may be problems if the RX interrupt
+  // occurs after reading the value of rx_buffer_head but before writing
+  // the value to rx_buffer_tail; the previous value of rx_buffer_head
+  // may be written to rx_buffer_tail, making it appear as if the buffer
+  // don't reverse this or there may be problems if the RX interrupt
+  // occurs after reading the value of rx_buffer_head but before writing
+  // the value to rx_buffer_tail; the previous value of rx_buffer_head
+  // may be written to rx_buffer_tail, making it appear as if the buffer
+  // were full, not empty.
+  _rx_buffer->head = _rx_buffer->tail;
 }
 
 void HardwareSerial::write(uint8_t c)
 {
-	while (!((*_ucsra) & (1 << _udre)))
-		;
+  while (!((*_ucsra) & (1 << _udre)))
+    ;
 
-	*_udr = c;
+  *_udr = c;
 }
 
 // Preinstantiate Objects //////////////////////////////////////////////////////
 
 #if defined(__AVR_ATmega8__)
-HardwareSerial Serial(&rx_buffer, &UBRRH, &UBRRL, &UCSRA, &UCSRB, &UDR, RXEN, TXEN, RXCIE, UDRE);
+HardwareSerial Serial(&rx_buffer, &UBRRH, &UBRRL, &UCSRA, &UCSRB, &UDR, RXEN, TXEN, RXCIE, UDRE, U2X);
 #else
-HardwareSerial Serial(&rx_buffer, &UBRR0H, &UBRR0L, &UCSR0A, &UCSR0B, &UDR0, RXEN0, TXEN0, RXCIE0, UDRE0);
+HardwareSerial Serial(&rx_buffer, &UBRR0H, &UBRR0L, &UCSR0A, &UCSR0B, &UDR0, RXEN0, TXEN0, RXCIE0, UDRE0, U2X0);
 #endif
 
 #if defined(__AVR_ATmega1280__)
-HardwareSerial Serial1(&rx_buffer1, &UBRR1H, &UBRR1L, &UCSR1A, &UCSR1B, &UDR1, RXEN1, TXEN1, RXCIE1, UDRE1);
-HardwareSerial Serial2(&rx_buffer2, &UBRR2H, &UBRR2L, &UCSR2A, &UCSR2B, &UDR2, RXEN2, TXEN2, RXCIE2, UDRE2);
-HardwareSerial Serial3(&rx_buffer3, &UBRR3H, &UBRR3L, &UCSR3A, &UCSR3B, &UDR3, RXEN3, TXEN3, RXCIE3, UDRE3);
+HardwareSerial Serial1(&rx_buffer1, &UBRR1H, &UBRR1L, &UCSR1A, &UCSR1B, &UDR1, RXEN1, TXEN1, RXCIE1, UDRE1, U2X1);
+HardwareSerial Serial2(&rx_buffer2, &UBRR2H, &UBRR2L, &UCSR2A, &UCSR2B, &UDR2, RXEN2, TXEN2, RXCIE2, UDRE2, U2X2);
+HardwareSerial Serial3(&rx_buffer3, &UBRR3H, &UBRR3L, &UCSR3A, &UCSR3B, &UDR3, RXEN3, TXEN3, RXCIE3, UDRE3, U2X3);
 #endif
-