#include <avr/io.h>

#include "board.h"

#include "excitation.h"

#define SPI_CS_HIGH() EXC_SPI_PORT |=  (1<<EXC_SPI_SS)

#define SPI_CS_LOW()  EXC_SPI_PORT &= ~(1<<EXC_SPI_SS)

void exc_setup(void) {

    SPI_CS_HIGH();

    EXC_SPI_DDR |= (1<<EXC_SPI_MOSI) | (1<<EXC_SPI_SCK) | (1<<EXC_SPI_SS);

    SPCR = (1<<SPE) | (1<<MSTR);

    EXC_EN_DDR |= (1<<EXC_VEN0) | (1<<EXC_VEN1);

}

static uint8_t spi_transfer(uint8_t data) {

    SPDR = data;

    while(! (SPSR & (1<<SPIF)));

    return SPDR;

}

void exc_power_on(bool on) {

    SPI_CS_LOW();

    spi_transfer(EXC_CMD_ACR_WRITE);

    spi_transfer(on? EXC_SHDN_bm : 0);

    SPI_CS_HIGH();

}

void exc_enable(uint8_t ch, uint8_t value) {

    exc_power_on(true);

    SPI_CS_LOW();

    spi_transfer(EXC_CMD_WRITE | ch);

    spi_transfer(value);

    SPI_CS_HIGH();

    EXC_EN_PORT |= (ch? (1<<EXC_VEN1) : (1<<EXC_VEN0));

}

void exc_disable(uint8_t ch) {

    EXC_EN_PORT &= ~(ch? (1<<EXC_VEN1) : (1<<EXC_VEN0));

    if((EXC_EN_PORT & ((1<<EXC_VEN1) | (1<<EXC_VEN0))) == 0) {

        exc_power_on(false);

    }

}