avr/spi/spi.c

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1.1 KiB
C
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#include <spi.h>
#include <util/delay.h>
void spi_initialize(spi_t *spi) {
set_line_direction(&spi->clock, LINE_OUT);
set_line_direction(&spi->data_out, LINE_OUT);
set_line_direction(&spi->data_in, LINE_IN);
set_line_direction(&spi->chip_select, LINE_OUT);
set_line(&spi->chip_select);
}
void spi_acquire(spi_t *spi) {
clear_line(&spi->chip_select);
}
void spi_release(spi_t *spi) {
set_line(&spi->chip_select);
}
uint8_t spi_transfer_byte(spi_t *spi, uint8_t output) {
uint8_t input = 0;
// int input_bit;
for (int i = 7; i >= 0; i--) {
clear_line(&spi->clock);
if (output & _BV(i)) {
set_line(&spi->data_out);
} else {
clear_line(&spi->data_out);
}
_delay_us(10);
set_line(&spi->clock);
_delay_us(10);
//input_bit = read_line(&spi->data_in);
//input <<= input_bit;
}
clear_line(&spi->clock);
_delay_us(10);
return input;
}
/*
void send_bytes(spi_t *line, u8 *byte, size_t length, u8 *input, size_t input_length) {
}
*/