75 lines
2.3 KiB
C
75 lines
2.3 KiB
C
/*
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Copyright 2012 Jun WAKO <wakojun@gmail.com>
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This software is licensed with a Modified BSD License.
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All of this is supposed to be Free Software, Open Source, DFSG-free,
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GPL-compatible, and OK to use in both free and proprietary applications.
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Additions and corrections to this file are welcome.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of the copyright holders nor the names of
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdbool.h>
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#include <avr/io.h>
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#include <avr/interrupt.h>
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#include "x68k.h"
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void x68k_init(void)
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{
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KBD_RX_INIT();
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}
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// RX ring buffer
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#define RBUF_SIZE 8
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static uint8_t rbuf[RBUF_SIZE];
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static uint8_t rbuf_head = 0;
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static uint8_t rbuf_tail = 0;
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uint8_t x68k_recv(void)
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{
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uint8_t data = 0;
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if (rbuf_head == rbuf_tail) {
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return 0;
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}
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data = rbuf[rbuf_tail];
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rbuf_tail = (rbuf_tail + 1) % RBUF_SIZE;
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return data;
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}
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// USART RX complete interrupt
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ISR(KBD_RX_VECT)
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{
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uint8_t next = (rbuf_head + 1) % RBUF_SIZE;
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if (next != rbuf_tail) {
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rbuf[rbuf_head] = KBD_RX_DATA;
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rbuf_head = next;
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}
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}
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