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#include <avr/io.h>
#include <avr/interrupt.h>
#include <stdint.h>
#include "mcu/mcu_def.h"
#include "buffers.h"
#ifndef _IOE_SPI_H_
#define _IOE_SPI_H_
#ifndef MCUSUPPORT_SPI
#error "No SPI interface is known on your mcu."
#endif
enum spiMode {
SPI_MODE_MASTER,
SPI_MODE_SLAVE
};
/*
* Initialize SPI
*
* Parameters:
* mode - Specify mode of SPI interface
*
* NOTE: Global interrupt must be enabled for right function of SPI.
* { SREG |= _BV(7) }
*/
void spi_init(enum spiMode mode);
/*
* Returns NULL when device is not busy.
* When device is busy return values in non-zero.
*/
int8_t spi_busy(void);
/*
* Blocks processor until device is not busy.
*/
void spi_join(void);
/*
* Swap bytes with slave over SPI.
* This function blocks execution until device isn't busy (transfer completed).
* WARNING: Invoke this only when interface is initialized in MASTER mode.
*/
uint8_t spi_send(uint8_t data);
/*
* Transfer byte to slave over SPI.
* This function isn't blocking execution until transfer is complete.
* Always call spi_join before this function when called outside of spi_receive().
* WARNING: Invoke this only when interface is initialized in MASTER mode.
*/
void spi_transfer(uint8_t data);
/*
* Expose data for next master request.
* Please don't use this when device is busy.
* Best place to call this is spi_receive().
* WARNING: Invoke this only when interface is initialized in SLAVE mode.
*/
void spi_expose(uint8_t data);
/*
* This function is called every time transfer is finished.
* And until return from this function interrupts are disabled.
*/
extern void (*spi_receive)(uint8_t data);
#endif /* _IOE_SPI_H_ */
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