version 0.1

wiring_serial.c

@@ -0,0 +1,212 @@
+/*
+  wiring_serial.c - serial functions.
+  Part of Arduino - http://www.arduino.cc/
+
+  Copyright (c) 2005-2006 David A. Mellis
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General
+  Public License along with this library; if not, write to the
+  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+  Boston, MA  02111-1307  USA
+
+  $Id: wiring.c 248 2007-02-03 15:36:30Z mellis $
+*/
+
+#include "wiring_private.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
+
+unsigned char rx_buffer[RX_BUFFER_SIZE];
+
+int rx_buffer_head = 0;
+int rx_buffer_tail = 0;
+
+void beginSerial(long baud)
+{
+#if defined(__AVR_ATmega168__)
+	UBRR0H = ((F_CPU / 16 + baud / 2) / baud - 1) >> 8;
+	UBRR0L = ((F_CPU / 16 + baud / 2) / baud - 1);
+	
+	// enable rx and tx
+	sbi(UCSR0B, RXEN0);
+	sbi(UCSR0B, TXEN0);
+	
+	// enable interrupt on complete reception of a byte
+	sbi(UCSR0B, RXCIE0);
+#else
+	UBRRH = ((F_CPU / 16 + baud / 2) / baud - 1) >> 8;
+	UBRRL = ((F_CPU / 16 + baud / 2) / baud - 1);
+	
+	// enable rx and tx
+	sbi(UCSRB, RXEN);
+	sbi(UCSRB, TXEN);
+	
+	// enable interrupt on complete reception of a byte
+	sbi(UCSRB, RXCIE);
+#endif
+	
+	// defaults to 8-bit, no parity, 1 stop bit
+}
+
+void serialWrite(unsigned char c)
+{
+#if defined(__AVR_ATmega168__)
+	while (!(UCSR0A & (1 << UDRE0)))
+		;
+
+	UDR0 = c;
+#else
+	while (!(UCSRA & (1 << UDRE)))
+		;
+
+	UDR = c;
+#endif
+}
+
+int serialAvailable()
+{
+	return (RX_BUFFER_SIZE + rx_buffer_head - rx_buffer_tail) % RX_BUFFER_SIZE;
+}
+
+int 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[rx_buffer_tail];
+		rx_buffer_tail = (rx_buffer_tail + 1) % RX_BUFFER_SIZE;
+		return c;
+	}
+}
+
+void 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
+	// were full, not empty.
+	rx_buffer_head = rx_buffer_tail;
+}
+
+#if defined(__AVR_ATmega168__)
+SIGNAL(SIG_USART_RECV)
+#else
+SIGNAL(SIG_UART_RECV)
+#endif
+{
+#if defined(__AVR_ATmega168__)
+	unsigned char c = UDR0;
+#else
+	unsigned char c = UDR;
+#endif
+
+	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[rx_buffer_head] = c;
+		rx_buffer_head = i;
+	}
+}
+
+void printMode(int mode)
+{
+	// do nothing, we only support serial printing, not lcd.
+}
+
+void printByte(unsigned char c)
+{
+	serialWrite(c);
+}
+
+void printNewline()
+{
+	printByte('\n');
+}
+
+void printString(const char *s)
+{
+	while (*s)
+		printByte(*s++);
+}
+
+void printIntegerInBase(unsigned long n, unsigned long base)
+{ 
+	unsigned char buf[8 * sizeof(long)]; // Assumes 8-bit chars. 
+	unsigned long i = 0;
+
+	if (n == 0) {
+		printByte('0');
+		return;
+	} 
+
+	while (n > 0) {
+		buf[i++] = n % base;
+		n /= base;
+	}
+
+	for (; i > 0; i--)
+		printByte(buf[i - 1] < 10 ?
+			'0' + buf[i - 1] :
+			'A' + buf[i - 1] - 10);
+}
+
+void printInteger(long n)
+{
+	if (n < 0) {
+		printByte('-');
+		n = -n;
+	}
+
+	printIntegerInBase(n, 10);
+}
+
+void printHex(unsigned long n)
+{
+	printIntegerInBase(n, 16);
+}
+
+void printOctal(unsigned long n)
+{
+	printIntegerInBase(n, 8);
+}
+
+void printBinary(unsigned long n)
+{
+	printIntegerInBase(n, 2);
+}
+
+/* Including print() adds approximately 1500 bytes to the binary size,
+ * so we replace it with the smaller and less-confusing printString(),
+ * printInteger(), etc.
+void print(const char *format, ...)
+{
+	char buf[256];
+	va_list ap;
+	
+	va_start(ap, format);
+	vsnprintf(buf, 256, format, ap);
+	va_end(ap);
+	
+	printString(buf);
+}
+*/