52 lines
1.0 KiB
C
52 lines
1.0 KiB
C
/*
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* doorlock-avr, AVR code of Binary Kitchen's doorlock
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*
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* Copyright (c) Binary Kitchen, 2018
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*
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* Authors:
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* Ralf Ramsauer <ralf@binary-kitchen.de>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*/
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#include <stddef.h>
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#include <avr/interrupt.h>
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#include <avr/io.h>
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#include "uart.h"
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#define UBRR_VAL ((F_OSC+UART_BAUD*8)/(UART_BAUD*16)-1)
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#define BAUD_REAL (F_OSC/(16*(UBRR_VAL+1)))
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#define BAUD_ERROR ((BAUD_REAL*1000)/UART_BAUD)
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#if ((BAUD_ERROR<985) || (BAUD_ERROR>1010))
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#warn BAUD_ERROR
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#error Choose another crystal. Baud error too high.
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#endif
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void uart_init()
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{
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// Enable receive and transmit
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UCSRB = (1<<RXEN)|(1<<TXEN)|(1<<RXCIE);
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// Asynchronous mode, 8N1
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UCSRC = (1<<UCSZ1)|(1<<UCSZ0);
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UBRRH = UBRR_VAL >> 8;
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UBRRL = UBRR_VAL & 0xFF;
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}
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void uart_putc(const char c)
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{
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while ( !(UCSRA & (1<<UDRE)) );
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UDR = (const unsigned char)c;
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}
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void uart_puts(const char* str)
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{
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do {
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uart_putc(*str);
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} while(*++str);
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}
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