1 files changed, 141 insertions, 8 deletions

diff --git a/cores/arduino/HardwareSerial.cpp b/cores/arduino/HardwareSerial.cpp
index aab7fc5..f8a959a 100755
--- a/cores/arduino/HardwareSerial.cpp
+++ b/cores/arduino/HardwareSerial.cpp
@@ -1,5 +1,5 @@
 /*
-  HarwareSerial.cpp - Hardware serial library for Wiring
+  HardwareSerial.cpp - Hardware serial library for Wiring
   Copyright (c) 2006 Nicholas Zambetti.  All right reserved.
 
   This library is free software; you can redistribute it and/or
@@ -23,36 +23,169 @@
 #include <string.h>
 #include <inttypes.h>
 #include "wiring.h"
+#include "wiring_private.h"
 
 #include "HardwareSerial.h"
 
+// Define constants and variables for buffering incoming serial data.  We're
+// using a ring buffer (I think), in which rx_buffer_head is the index of the
+// location to which to write the next incoming character and rx_buffer_tail
+// is the index of the location from which to read.
+#define RX_BUFFER_SIZE 128
+
+struct ring_buffer {
+  unsigned char buffer[RX_BUFFER_SIZE];
+  int head;
+  int tail;
+};
+
+ring_buffer rx_buffer = { { 0 }, 0, 0 };
+
+#if defined(__AVR_ATmega1280__)
+ring_buffer rx_buffer1 = { { 0 }, 0, 0 };
+ring_buffer rx_buffer2 = { { 0 }, 0, 0 };
+ring_buffer rx_buffer3 = { { 0 }, 0, 0 };
+#endif
+
+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;
+	}
+}
+
+#if defined(__AVR_ATmega1280__)
+
+SIGNAL(SIG_USART0_RECV)
+{
+	unsigned char c = UDR0;
+  store_char(c, &rx_buffer);
+}
+
+SIGNAL(SIG_USART1_RECV)
+{
+	unsigned char c = UDR1;
+  store_char(c, &rx_buffer1);
+}
+
+SIGNAL(SIG_USART2_RECV)
+{
+	unsigned char c = UDR2;
+  store_char(c, &rx_buffer2);
+}
+
+SIGNAL(SIG_USART3_RECV)
+{
+	unsigned char c = UDR3;
+  store_char(c, &rx_buffer3);
+}
+
+#else
+
+#if defined(__AVR_ATmega8__)
+SIGNAL(SIG_UART_RECV)
+#else
+SIGNAL(USART_RX_vect)
+#endif
+{
+#if defined(__AVR_ATmega8__)
+	unsigned char c = UDR;
+#else
+	unsigned char c = UDR0;
+#endif
+  store_char(c, &rx_buffer);
+}
+
+#endif
+
+// Constructors ////////////////////////////////////////////////////////////////
+
+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)
+{
+  _rx_buffer = rx_buffer;
+  _ubrrh = ubrrh;
+  _ubrrl = ubrrl;
+  _ucsra = ucsra;
+  _ucsrb = ucsrb;
+  _udr = udr;
+  _rxen = rxen;
+  _txen = txen;
+  _rxcie = rxcie;
+  _udre = udre;
+}
+
 // Public Methods //////////////////////////////////////////////////////////////
 
 void HardwareSerial::begin(long speed)
 {
-  beginSerial(speed);
+	*_ubrrh = ((F_CPU / 16 + speed / 2) / speed - 1) >> 8;
+	*_ubrrl = ((F_CPU / 16 + speed / 2) / speed - 1);
+  sbi(*_ucsrb, _rxen);
+  sbi(*_ucsrb, _txen);
+  sbi(*_ucsrb, _rxcie);
 }
 
 uint8_t HardwareSerial::available(void)
 {
-  return serialAvailable();
+	return (RX_BUFFER_SIZE + _rx_buffer->head - _rx_buffer->tail) % RX_BUFFER_SIZE;
 }
 
 int HardwareSerial::read(void)
 {
-  return serialRead();
+	// 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()
 {
-  serialFlush();
+	// 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 b) {
-  serialWrite(b);
+void HardwareSerial::write(uint8_t c)
+{
+	while (!((*_ucsra) & (1 << _udre)))
+		;
+
+	*_udr = c;
 }
 
 // Preinstantiate Objects //////////////////////////////////////////////////////
 
-HardwareSerial Serial = HardwareSerial();
+#if defined(__AVR_ATmega8__)
+HardwareSerial Serial(&rx_buffer, &UBRRH, &UBRRL, &UCSRA, &UCSRB, &UDR, RXEN, TXEN, RXCIE, UDRE);
+#else
+HardwareSerial Serial(&rx_buffer, &UBRR0H, &UBRR0L, &UCSR0A, &UCSR0B, &UDR0, RXEN0, TXEN0, RXCIE0, UDRE0);
+#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);
+#endif