91 lines
1.6 KiB
C
91 lines
1.6 KiB
C
/*
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* Copyright 2011 Mika Tuupola
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*
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* Licensed under the MIT license:
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* http://www.opensource.org/licenses/mit-license.php
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*
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*/
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#include <avr/io.h>
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#include <stdio.h>
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#ifndef F_CPU
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#define F_CPU 16000000UL
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#endif
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#ifndef BAUD
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#define BAUD 9600
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#endif
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#include <util/setbaud.h>
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#if defined (UBRR0H)
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#warning UART0
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#define UBRRxH UBRR0H
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#define UBRRxL UBRR0L
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#define UCSRxA UCSR0A
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#define U2Xx U2X0
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#define UCSRxC UCSR0C
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#define UCSZx1 UCSZ01
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#define UCSZx0 UCSZ00
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#define UCSRxB UCSR0B
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#define RXENx RXEN0
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#define TXENx TXEN0
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#define UDREx UDRE0
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#define RXCx RXC0
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#define UDRx UDR0
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#define UDRIEx UDRIE0
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#elif defined (UBRR1H)
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#warning UART1
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#define UBRRxH UBRR1H
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#define UBRRxL UBRR1L
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#define UCSRxA UCSR1A
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#define U2Xx U2X1
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#define UCSRxC UCSR1C
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#define UCSZx1 UCSZ11
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#define UCSZx0 UCSZ10
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#define UCSRxB UCSR1B
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#define RXENx RXEN1
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#define TXENx TXEN1
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#define UDREx UDRE1
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#define RXCx RXC1
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#define UDRx UDR1
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#define UDRIEx UDRIE1
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#else
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#error No UART?
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#endif
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/* http://www.cs.mun.ca/~rod/Winter2007/4723/notes/serial/serial.html */
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void uart_init(void) {
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UBRRxH = UBRRH_VALUE;
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UBRRxL = UBRRL_VALUE;
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#if USE_2X
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UCSRxA |= _BV(U2Xx);
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#else
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UCSRxA &= ~(_BV(U2Xx));
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#endif
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UCSRxC = _BV(UCSZx1) | _BV(UCSZx0); /* 8-bit data */
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UCSRxB = _BV(RXENx) | _BV(TXENx); /* Enable RX and TX */
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}
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int uart_putchar(char c, FILE *stream) {
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if (c == '\n') {
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uart_putchar('\r', stream);
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}
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loop_until_bit_is_set(UCSRxA, UDREx);
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UDRx = c;
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return 0;
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}
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int uart_getchar(FILE *stream) {
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loop_until_bit_is_set(UCSRxA, RXCx);
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return UDRx;
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}
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