96 lines
2.2 KiB
C
96 lines
2.2 KiB
C
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/*
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Copyright 2016 Kai Ryu <kai1103@gmail.com>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <avr/interrupt.h>
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#include <avr/wdt.h>
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#include <util/delay.h>
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#include "i2cmaster.h"
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#include "i2c_wrapper.h"
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#include "debug.h"
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#define wdt_intr_enable(value) \
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__asm__ __volatile__ ( \
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"in __tmp_reg__,__SREG__" "\n\t" \
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"cli" "\n\t" \
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"wdr" "\n\t" \
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"sts %0,%1" "\n\t" \
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"out __SREG__,__tmp_reg__" "\n\t" \
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"sts %0,%2" "\n\t" \
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: /* no outputs */ \
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: "M" (_SFR_MEM_ADDR(_WD_CONTROL_REG)), \
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"r" (_BV(_WD_CHANGE_BIT) | _BV(WDE)), \
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"r" ((uint8_t) ((value & 0x08 ? _WD_PS3_MASK : 0x00) | \
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_BV(WDIE) | (value & 0x07)) ) \
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: "r0" \
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)
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#define SCL_CLOCK 400000L
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#define SCL_DURATION (1000000L/SCL_CLOCK)/2
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static uint8_t i2c_wdt_enabled = 0;
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extern uint8_t i2c_force_stop;
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static void wdt_init(void);
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void i2c_wrapper_init(void)
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{
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/* init i2c */
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i2c_init();
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/* init watch dog */
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wdt_init();
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}
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void i2c_wrapper_task(void)
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{
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/* reset watch dog counter */
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wdt_reset();
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}
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void wdt_init(void)
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{
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cli();
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wdt_reset();
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wdt_intr_enable(WDTO_2S);
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sei();
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}
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ISR(WDT_vect)
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{
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xprintf("i2c timeout\n");
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/* let slave to release SDA */
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TWCR = 0;
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DDRD |= (1<<PD0);
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DDRD &= ~(1<<PD1);
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if (!(PIND & (1<<PD1))) {
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for (uint8_t i = 0; i < 9; i++) {
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PORTD &= ~(1<<PD0);
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_delay_us(SCL_DURATION);
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PORTD |= (1<<PD0);
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_delay_us(SCL_DURATION);
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}
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}
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/* send stop condition */
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TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
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/* escape from loop */
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i2c_force_stop = 1;
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}
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