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/*
* 74HCT4094 shift register driver
*
* Copyright (C) 2009-2016 Michael Buesch <m@bues.ch>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include "4094.h"
#include "util.h"
#include <avr/io.h>
#define _sr4094_clear(pin) \
SR4094_##pin##_PORT = (uint8_t)(SR4094_##pin##_PORT & ~(1 << SR4094_##pin##_BIT))
#define _sr4094_set(pin) \
SR4094_##pin##_PORT = (uint8_t)(SR4094_##pin##_PORT | (1u << SR4094_##pin##_BIT))
static inline void sr4094_transfer_start(void)
{
_sr4094_clear(STROBE);
}
static inline void sr4094_transfer_end(void)
{
_sr4094_set(STROBE);
}
static void sr4094_put_byte(uint8_t data)
{
uint8_t mask = 0x80;
do {
if (data & mask)
_sr4094_set(DATA);
else
_sr4094_clear(DATA);
_sr4094_set(CLOCK);
nop();
nop();
_sr4094_clear(CLOCK);
mask >>= 1;
} while (mask);
}
void sr4094_put_data(void *_data, uint8_t nr_chips)
{
uint8_t *data = _data;
uint8_t i;
sr4094_transfer_start();
for (i = 0; i < nr_chips; i++)
sr4094_put_byte(data ? data[i] : 0);
sr4094_transfer_end();
}
void sr4094_outen(uint8_t enable)
{
if (enable)
_sr4094_set(OUTEN);
else
_sr4094_clear(OUTEN);
}
void sr4094_init(void *initial_data, uint8_t nr_chips)
{
sr4094_outen(0);
SR4094_OUTEN_DDR |= (1 << SR4094_OUTEN_BIT);
_sr4094_clear(DATA);
SR4094_DATA_DDR |= (1 << SR4094_DATA_BIT);
_sr4094_clear(CLOCK);
SR4094_CLOCK_DDR |= (1 << SR4094_CLOCK_BIT);
_sr4094_set(STROBE);
SR4094_STROBE_DDR |= (1 << SR4094_STROBE_BIT);
sr4094_put_data(initial_data, nr_chips);
}
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