spi/spi.hpp

#pragma once

#include "../inout/inout.h"

#include <avr/io.h>

namespace spi {

class Spi {
  public:
	enum class ClockDiv {
		CLKDIV_4 = 0,
		CLKDIV_16 = 1,
		CLKDIV_64 = 2,
		CLKDIV_128 = 3,

		CLKDIV_2X_2 = 4,
		CLKDIV_2X_8 = 5,
		CLKDIV_2X_32 = 6,
		CLKDIV_2X_64 = 7
	};

	enum class Mode { MODE_0 = 0, MODE_1 = 1, MODE_2 = 2, MODE_3 = 3 };

  private:
	static void setCPOL(bool bCPOL);
	static void setCPHA(bool bCPHA);

	static constexpr InOut::Pin sm_enmSCK = InOut::Pin::P_B5;
	static constexpr InOut::Pin sm_enmMISO = InOut::Pin::P_B4;
	static constexpr InOut::Pin sm_enmMOSI = InOut::Pin::P_B3;
	static constexpr InOut::Pin sm_enmSS = InOut::Pin::P_B2;

	static InOutPin sm_cSCK;
	static InOutPin sm_cMISO;
	static InOutPin sm_cMOSI;
	static InOutPin sm_cSS;

  public:
	static void init(ClockDiv enmClockDiv = ClockDiv::CLKDIV_128, Mode enmMode = Mode::MODE_0, bool bMaster = true,
	                 bool bLSBFirst = false, bool bMISOPullup = false);
	static void deinit();
	static void setClockDiv(ClockDiv enmClockDiv);
	static void setMode(Mode enmMode);
	static void setMaster(bool bMaster);
	static void setBitOrder(bool bLSBFirst);

	static uint8_t transfer(uint8_t ui8Data);

	static void select(bool bSelect);
};

//////////////////////////////////////////////////////////////////////////
InOutPin Spi::sm_cSCK;
InOutPin Spi::sm_cMISO;
InOutPin Spi::sm_cMOSI;
InOutPin Spi::sm_cSS;

//////////////////////////////////////////////////////////////////////////
void Spi::setCPOL(bool bCPOL)
{
	if (bCPOL) {
		SPCR |= (1 << CPOL);
	} else {
		SPCR &= ~(1 << CPOL);
	}
}

//////////////////////////////////////////////////////////////////////////
void Spi::setCPHA(bool bCPHA)
{
	if (bCPHA) {
		SPCR |= (1 << CPHA);
	} else {
		SPCR &= ~(1 << CPHA);
	}
}

//////////////////////////////////////////////////////////////////////////
void Spi::init(ClockDiv enmClockDiv /* = ClockDiv::CLKDIV_128 */, Mode enmMode /* = Mode::MODE_0 */,
               bool bMaster /* = true */, bool bLSBFirst /* = false */, bool bMISOPullup /* = false */)
{
	sm_cSCK.setPin(sm_enmSCK);
	sm_cMISO.setPin(sm_enmMISO);
	sm_cMOSI.setPin(sm_enmMOSI);
	sm_cSS.setPin(sm_enmSS);

	if (bMaster) {
		sm_cSS.write(true);

		sm_cSCK.setDirection(InOut::Dir::D_OUT, false);
		sm_cMISO.setDirection(InOut::Dir::D_IN, bMISOPullup);
		sm_cMOSI.setDirection(InOut::Dir::D_OUT, false);
		sm_cSS.setDirection(InOut::Dir::D_OUT, false);
	} else {
		sm_cSCK.setDirection(InOut::Dir::D_IN, false);
		sm_cMISO.setDirection(InOut::Dir::D_OUT, false);
		sm_cMOSI.setDirection(InOut::Dir::D_IN, false);
		sm_cSS.setDirection(InOut::Dir::D_IN, true);
	}

	setClockDiv(enmClockDiv);
	setMode(enmMode);
	setMaster(bMaster);
	setBitOrder(bLSBFirst);

	SPCR |= (1 << SPE);
}

//////////////////////////////////////////////////////////////////////////
void Spi::deinit()
{
	SPCR = 0;

	sm_cSCK.setDirection(InOut::Dir::D_IN, false);
	sm_cMISO.setDirection(InOut::Dir::D_IN, false);
	sm_cMOSI.setDirection(InOut::Dir::D_IN, false);
	sm_cSS.setDirection(InOut::Dir::D_IN, false);
}

//////////////////////////////////////////////////////////////////////////
void Spi::setClockDiv(ClockDiv enmClockDiv)
{
	uint8_t ui8ClockDiv = static_cast<uint8_t>(enmClockDiv);

	if (ui8ClockDiv & 1) {
		SPCR |= (1 << SPR0);
	} else {
		SPCR &= ~(1 << SPR0);
	}

	if (ui8ClockDiv & (1 << 1)) {
		SPCR |= (1 << SPR1);
	} else {
		SPCR &= ~(1 << SPR1);
	}

	if (ui8ClockDiv & (1 << 2)) {
		SPSR |= (1 << SPI2X);
	} else {
		SPSR &= ~(1 << SPI2X);
	}
}

//////////////////////////////////////////////////////////////////////////
void Spi::setMode(Mode enmMode)
{
	if (enmMode == Mode::MODE_0 || enmMode == Mode::MODE_1) {
		setCPOL(false);
	} else {
		setCPOL(true);
	}

	if (enmMode == Mode::MODE_0 || enmMode == Mode::MODE_2) {
		setCPHA(false);
	} else {
		setCPHA(true);
	}
}

//////////////////////////////////////////////////////////////////////////
void Spi::setMaster(bool bMaster)
{
	if (bMaster) {
		SPCR |= (1 << MSTR);
	} else {
		SPCR &= ~(1 << MSTR);
	}
}

//////////////////////////////////////////////////////////////////////////
void Spi::setBitOrder(bool bLSBFirst)
{
	if (bLSBFirst) {
		SPCR |= (1 << DORD);
	} else {
		SPCR &= ~(1 << DORD);
	}
}

//////////////////////////////////////////////////////////////////////////
uint8_t Spi::transfer(uint8_t ui8Data)
{
	SPDR = ui8Data;
	while (!(SPSR & (1 << SPIF)))
		;
	return SPDR;
}

//////////////////////////////////////////////////////////////////////////
void Spi::select(bool bSelect)
{
	sm_cSS.write(!bSelect);
}

} // namespace spi