#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#include <util/delay.h>

#include <tabby/printer.h>
#include <tabby/avr/uart.h>
#include <tabby/avr.h>

void tabby_avr_link_init_master() {
    SC_OUTPUT();
    SO_OUTPUT();

    SI_INPUT();
    SI_PULLUP();

    SC_HIGH();
    SO_LOW();
}

void tabby_avr_link_init_slave() {
    SS_INPUT();
    SC_INPUT();
    SI_INPUT();
    SO_OUTPUT();

    /*
     * Set SPI slave mode, and shift in/out most significant bit first
     */
    SPCR &= ~((1 << MSTR) | (1 << DORD));

    /*
     * Enable SPI in Mode 3 with interrupts, clock nominally high, output on
     * falling edge, input on rising edge
     */
    SPCR |= (1 << CPOL) | (1 << CPHA) | (1 << SPIE) | (1 << SPE);

    /*
     * Initialize the SPI Data Register and serial buffer
     */
    SPDR = 0;
}

uint8_t tabby_avr_link_send_byte(uint8_t value) {
    uint8_t i, ret = 0;

    for (i=0; i<8; i++) {
        SC_LOW();

        if (value & 0x80) {
            SO_HIGH();
        } else {
            SO_LOW();
        }

        _delay_us(SPI_PULSE_USEC);

        value <<= 1;
        ret   <<= 1;

        SC_HIGH();

        if (SI_IS_HIGH()) {
            ret |= 1;
        }

        _delay_us(SPI_PULSE_USEC);
    }

    return ret;
}