43 lines
1.6 KiB
C
43 lines
1.6 KiB
C
/* sd_spi.h
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Copyright 2021 Carl John Kugler III
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Licensed under the Apache License, Version 2.0 (the License); you may not use
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this file except in compliance with the License. You may obtain a copy of the
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License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software distributed
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under the License is distributed on an AS IS BASIS, WITHOUT WARRANTIES OR
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CONDITIONS OF ANY KIND, either express or implied. See the License for the
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specific language governing permissions and limitations under the License.
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*/
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#ifndef _SD_SPI_H_
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#define _SD_SPI_H_
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#include <stdint.h>
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#include "sd_card.h"
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/* Transfer tx to SPI while receiving SPI to rx.
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tx or rx can be NULL if not important. */
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bool sd_spi_transfer(sd_card_t *pSD, const uint8_t *tx, uint8_t *rx, size_t length);
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uint8_t sd_spi_write(sd_card_t *pSD, const uint8_t value);
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void sd_spi_deselect_pulse(sd_card_t *pSD);
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void sd_spi_acquire(sd_card_t *pSD);
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void sd_spi_release(sd_card_t *pSD);
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void sd_spi_go_low_frequency(sd_card_t *this);
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void sd_spi_go_high_frequency(sd_card_t *this);
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/*
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After power up, the host starts the clock and sends the initializing sequence on the CMD line.
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This sequence is a contiguous stream of logical ‘1’s. The sequence length is the maximum of 1msec,
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74 clocks or the supply-ramp-uptime; the additional 10 clocks
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(over the 64 clocks after what the card should be ready for communication) is
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provided to eliminate power-up synchronization problems.
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*/
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void sd_spi_send_initializing_sequence(sd_card_t * pSD);
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#endif
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/* [] END OF FILE */
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