55 lines
1.7 KiB
C
55 lines
1.7 KiB
C
/*
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Copyright 2022, Savanni D'Gerinel <savanni@luminescent-dreams.com>
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This file is part of Savanni's AVR library.
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Lumeto is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
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Lumeto 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.
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You should have received a copy of the GNU General Public License along with Lumeto. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <util/delay.h>
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#include "spi.h"
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void spi_initialize(spi_t *spi) {
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dio_set_direction(&spi->clock, LINE_OUT);
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dio_set_direction(&spi->data_out, LINE_OUT);
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dio_set_direction(&spi->data_in, LINE_IN);
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dio_set_direction(&spi->chip_select, LINE_OUT);
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dio_set(&spi->chip_select, 1);
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}
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void spi_acquire(spi_t *spi) {
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dio_set(&spi->chip_select, 0);
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}
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void spi_release(spi_t *spi) {
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dio_set(&spi->chip_select, 1);
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}
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uint8_t spi_transceive(spi_t *spi, uint8_t output) {
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uint8_t input = 0;
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int input_bit;
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for (int i = 7; i >= 0; i--) {
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dio_set(&spi->clock, 0);
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if (output & _BV(i)) {
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dio_set(&spi->data_out, 1);
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} else {
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dio_set(&spi->data_out, 0);
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}
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_delay_us(10);
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dio_set(&spi->clock, 1);
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input_bit = dio_read(&spi->data_in);
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input = (input << 1) | input_bit;
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_delay_us(10);
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}
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dio_set(&spi->clock, 0);
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_delay_us(10);
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return input;
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}
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