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- /*
- Copyright 2010,2011,2012,2013 Jun WAKO <[email protected]>
-
- This software is licensed with a Modified BSD License.
- All of this is supposed to be Free Software, Open Source, DFSG-free,
- GPL-compatible, and OK to use in both free and proprietary applications.
- Additions and corrections to this file are welcome.
-
-
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions are met:
-
- * Redistributions of source code must retain the above copyright
- notice, this list of conditions and the following disclaimer.
-
- * Redistributions in binary form must reproduce the above copyright
- notice, this list of conditions and the following disclaimer in
- the documentation and/or other materials provided with the
- distribution.
-
- * Neither the name of the copyright holders nor the names of
- contributors may be used to endorse or promote products derived
- from this software without specific prior written permission.
-
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- POSSIBILITY OF SUCH DAMAGE.
- */
-
- /*
- * PS/2 protocol Pin interrupt version
- */
-
- #include <stdbool.h>
- #include <avr/interrupt.h>
- #include <util/delay.h>
- #include "pbuff.h"
- #include "xt.h"
- #include "xt_io.h"
- #include "wait.h"
- #include "print.h"
-
- void xt_host_init(void)
- {
- XT_INT_INIT();
- XT_INT_ON();
- }
-
- /* get data received by interrupt */
- uint8_t xt_host_recv(void)
- {
- if (pbuf_has_data()) {
- return pbuf_dequeue();
- } else {
- return 0;
- }
- }
-
- ISR(XT_INT_VECT)
- {
- static enum {
- INIT,
- BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7,
- STOP,
- } state = INIT;
- static uint8_t data = 0;
- // wait for clock falling edge
- if(state != INIT)
- wait_clock_lo(70);
-
- switch (state) {
- case INIT:
- if (data_in())
- state++;
- break;
- case BIT0:
- case BIT1:
- case BIT2:
- case BIT3:
- case BIT4:
- case BIT5:
- case BIT6:
- case BIT7:
- state++;
- data >>= 1;
- if (data_in()) {
- data |= 0x80;
- }
- break;
- case STOP:
- if (!data_in())
- goto DONE;
- pbuf_enqueue(data);
- goto DONE;
- break;
- default:
- goto DONE;
- }
- goto RETURN;
- DONE:
- state = INIT;
- data = 0;
- RETURN:
- return;
- }
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