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#include "spi.h"
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#include <stdint.h>
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#include <avr/io.h>
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#include "utils.h"
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#include "pins.h"
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void spi_init(const enum spi_divider divider)
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{
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DDRB |= pin(PIN_SPI_SS) | pin(PIN_SPI_MOSI) | pin(PIN_SPI_SCK); // Outputs
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DDRB &= ~pin(PIN_SPI_MISO); // Inputs
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PORTB |= pin(PIN_SPI_MISO); // Pull it up
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// Configure SPI as master
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SPCR = _BV(SPE) | _BV(MSTR) | (divider & 3);
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SPSR = (divider & 4) >> 2;
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}
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void spi_off(void)
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{
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SPCR = 0;
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SPSR = 1;
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}
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uint8_t spi_transfer(const uint8_t data)
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{
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SPDR = data;
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__asm__ volatile ("nop");
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while (!(SPSR & _BV(SPIF))) __asm__ volatile ("nop");
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return SPDR;
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}
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