spi.h

Go to the documentation of this file.

/*
 * atMETEO - An ATmega based weather station
 * Copyright (C) 2014-2015 Christian Fetzer
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#pragma once

#include <inttypes.h>  // AVR toolchain doesn't offer cinttypes header

#include "lib/utils.h"

#include "pin.h"

namespace Avr
{

template <class TCsDigitalIo, uint8_t csPinNumber>
class Spi
{
public:
    static Spi& instance()
    {
        return s_instance;
    }

    void select()
    {
        s_cs.on();
    }

    void deselect()
    {
        s_cs.off();
    }

    uint8_t transceive(uint8_t value)
    {
        SPDR = value;
        while (!(Sensors::bitRead(SPSR, SPIF)));
        return SPDR;
    }

    void transmit(uint8_t value)
    {
        transceive(value);
    }

    uint8_t receive()
    {
        return transceive(0x00);
    }

private:
    static Spi s_instance;
    Avr::OutputPinInverted<TCsDigitalIo, csPinNumber> s_cs;

    Spi()
    {
        Avr::OutputPin<Avr::DigitalIoB, PB5> clk;
        Avr::OutputPin<Avr::DigitalIoB, PB3> mosi;
        Avr::InputPin<Avr::DigitalIoB, PB4> miso;

        deselect();
        Sensors::bitSet(SPCR, SPE);   // Enable SPI
        Sensors::bitSet(SPCR, MSTR);  // SPI Master
        Sensors::bitSet(SPSR, SPI2X); // Clock rate
    }
};

template <class TCsDigitalIo, uint8_t csPinNumber>
Avr::Spi<TCsDigitalIo, csPinNumber>
Spi<TCsDigitalIo, csPinNumber>::s_instance = Spi();
  // \addtogroup libtarget_spi

}  // namespace Avr