Make use of C++ standard library

config.hpp

@@ -1,5 +1,9 @@
 #pragma once
 
+#include <cstdint>
+
+#include "../io/io.hpp"
+
 namespace spi {
 
 enum class ClockDiv {
@@ -32,12 +36,27 @@ enum class BitOrder {
 };
 
 template <ClockDiv freq = ClockDiv::DIV_128, Mode mode = Mode::MODE_0, Side side = Side::MASTER,
-          BitOrder bitOrder = BitOrder::MSB_FIRST, bool pullup = false>
-struct Config {
+          BitOrder bitOrder = BitOrder::MSB_FIRST, io::P ssPin = io::P::B2, bool pullup = false>
+struct HardwareConfig {
 	static constexpr auto FREQ = freq;
 	static constexpr auto MODE = mode;
 	static constexpr auto SIDE = side;
 	static constexpr auto BIT_ORDER = bitOrder;
+	static constexpr auto SS_PIN = ssPin;
+	static constexpr auto PULLUP = pullup;
+};
+
+template <io::P sckPin, io::P misoPin, io::P mosiPin, io::P ssPin, std::uint32_t freq = 100'000,
+          Mode mode = Mode::MODE_0, BitOrder bitOrder = BitOrder::MSB_FIRST, std::uint8_t bits = 8, bool pullup = false>
+struct SoftwareConfig {
+	static constexpr auto SCK_PIN = sckPin;
+	static constexpr auto MISO_PIN = misoPin;
+	static constexpr auto MOSI_PIN = mosiPin;
+	static constexpr auto SS_PIN = ssPin;
+	static constexpr auto FREQ = freq;
+	static constexpr auto MODE = mode;
+	static constexpr auto BIT_ORDER = bitOrder;
+	static constexpr auto BITS = bits;
 	static constexpr auto PULLUP = pullup;
 };
 

hardware.hpp

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <cstdint>
+
 #include "../io/io.hpp"
 
 namespace spi {
@@ -9,6 +11,8 @@ namespace spi {
 template <class Cfg>
 class Hardware {
   public:
+	using word_t = std::uint8_t;
+
 	static void init()
 	{
 		if constexpr (Cfg::SIDE == Side::MASTER) {
@@ -32,10 +36,10 @@ class Hardware {
 		setMaster();
 		setBitOrder();
 
-		SPCR |= (1 << SPE);
+		SPCR = SPCR | (1 << SPE);
 	}
 
-	static uint8_t transfer(uint8_t data)
+	static word_t transfer(word_t data)
 	{
 		SPDR = data;
 		while (!(SPSR & (1 << SPIF)))
@@ -52,28 +56,28 @@ class Hardware {
 	static io::Pin<io::P::B5> sm_sck;
 	static io::Pin<io::P::B4> sm_miso;
 	static io::Pin<io::P::B3> sm_mosi;
-	static io::Pin<io::P::B2> sm_ss;
+	static io::Pin<Cfg::SS_PIN> sm_ss;
 
 	static void setClockDiv()
 	{
-		uint8_t ui8ClockDiv = static_cast<uint8_t>(Cfg::FREQ);
+		std::uint8_t ui8ClockDiv = static_cast<std::uint8_t>(Cfg::FREQ);
 
 		if (ui8ClockDiv & 1) {
-			SPCR |= (1 << SPR0);
+			SPCR = SPCR | (1 << SPR0);
 		} else {
-			SPCR &= ~(1 << SPR0);
+			SPCR = SPCR & ~(1 << SPR0);
 		}
 
 		if (ui8ClockDiv & (1 << 1)) {
-			SPCR |= (1 << SPR1);
+			SPCR = SPCR | (1 << SPR1);
 		} else {
-			SPCR &= ~(1 << SPR1);
+			SPCR = SPCR & ~(1 << SPR1);
 		}
 
 		if (ui8ClockDiv & (1 << 2)) {
-			SPSR |= (1 << SPI2X);
+			SPSR = SPSR | (1 << SPI2X);
 		} else {
-			SPSR &= ~(1 << SPI2X);
+			SPSR = SPSR & ~(1 << SPI2X);
 		}
 	}
 
@@ -95,35 +99,35 @@ class Hardware {
 	static void setMaster()
 	{
 		if constexpr (Cfg::SIDE == Side::MASTER) {
-			SPCR |= (1 << MSTR);
+			SPCR = SPCR | (1 << MSTR);
 		} else {
-			SPCR &= ~(1 << MSTR);
+			SPCR = SPCR & ~(1 << MSTR);
 		}
 	}
 
 	static void setBitOrder()
 	{
 		if constexpr (Cfg::BIT_ORDER == BitOrder::LSB_FIRST) {
-			SPCR |= (1 << DORD);
+			SPCR = SPCR | (1 << DORD);
 		} else {
-			SPCR &= ~(1 << DORD);
+			SPCR = SPCR & ~(1 << DORD);
 		}
 	}
 
 	static void setCPOL(bool bCPOL)
 	{
 		if (bCPOL) {
-			SPCR |= (1 << CPOL);
+			SPCR = SPCR | (1 << CPOL);
 		} else {
-			SPCR &= ~(1 << CPOL);
+			SPCR = SPCR & ~(1 << CPOL);
 		}
 	}
 	static void setCPHA(bool bCPHA)
 	{
 		if (bCPHA) {
-			SPCR |= (1 << CPHA);
+			SPCR = SPCR | (1 << CPHA);
 		} else {
-			SPCR &= ~(1 << CPHA);
+			SPCR = SPCR & ~(1 << CPHA);
 		}
 	}
 };

software.hpp

@@ -0,0 +1,114 @@
+#pragma once
+
+#include "../clock.hpp"
+
+#include <type_traits>
+#include <utility>
+
+#include <cstdint>
+
+#include <avr/interrupt.h>
+
+#include "../io/io.hpp"
+#include "../util/util.hpp"
+
+namespace spi {
+
+template <typename Cfg>
+class Software {
+	static constexpr double calcClockDelay()
+	{
+		constexpr auto staticClockCycles = 10;
+		constexpr auto maxFrequency = F_CPU / staticClockCycles;
+		static_assert(Cfg::FREQ <= maxFrequency, "SPI frequency not achievable using selected clock speed");
+		constexpr auto staticDelay = (1.0 * 1000 * 1000 / maxFrequency);
+		const auto delayUs = ((1.0 * 1000 * 1000 / Cfg::FREQ) - staticDelay) / 2;
+		return (delayUs > 0 ? delayUs : 0);
+	}
+
+  public:
+	static_assert(Cfg::BITS >= 1 && Cfg::BITS <= 64, "Word size must be in range [1-64]");
+	// clang-format off
+	using word_t = std::conditional_t<Cfg::BITS <=  8, std::uint8_t,
+	               std::conditional_t<Cfg::BITS <= 16, std::uint16_t,
+	               std::conditional_t<Cfg::BITS <= 32, std::uint32_t,
+	                                                   std::uint64_t>>>;
+	// clang-format on
+
+	static void init()
+	{
+		sm_sck = ((Cfg::MODE == Mode::MODE_0 || Cfg::MODE == Mode::MODE_1) ? false : true);
+		sm_ss = true;
+
+		sm_sck.dir(io::Dir::OUT);
+		sm_miso.dir(io::Dir::IN);
+		sm_miso.pullup(Cfg::PULLUP);
+		sm_mosi.dir(io::Dir::OUT);
+		sm_ss.dir(io::Dir::OUT);
+	}
+
+	static word_t transfer(const word_t data)
+	{
+		const auto oldInterruptState = disableInterrupts();
+
+		auto dataIn = word_t{};
+
+		util::for_constexpr(
+		    [&](const auto idx) {
+			    constexpr auto i = idx.value;
+			    constexpr auto bitPos = (Cfg::BIT_ORDER == BitOrder::MSB_FIRST ? Cfg::BITS - i - 1 : i);
+
+			    if constexpr (Cfg::MODE == Mode::MODE_0 || Cfg::MODE == Mode::MODE_2) {
+				    sm_mosi = data >> bitPos & 1;
+				    _delay_us(DELAY_US);
+				    sm_sck.toggle();
+
+				    const auto receivedBit = sm_miso.read();
+				    dataIn |= word_t{receivedBit} << bitPos;
+				    _delay_us(DELAY_US);
+				    sm_sck.toggle();
+			    } else {
+				    sm_sck.toggle();
+				    sm_mosi = data >> bitPos & 1;
+				    _delay_us(DELAY_US);
+
+				    sm_sck.toggle();
+				    const auto receivedBit = sm_miso.read();
+				    dataIn |= word_t{receivedBit} << bitPos;
+				    _delay_us(DELAY_US);
+			    }
+		    },
+		    std::make_index_sequence<Cfg::BITS>{});
+
+		enableInterrupts(oldInterruptState);
+
+		return dataIn;
+	}
+
+	static void select(const bool selectState)
+	{
+		sm_ss = !selectState;
+	}
+
+  private:
+	static io::Pin<Cfg::SCK_PIN> sm_sck;
+	static io::Pin<Cfg::MISO_PIN> sm_miso;
+	static io::Pin<Cfg::MOSI_PIN> sm_mosi;
+	static io::Pin<Cfg::SS_PIN> sm_ss;
+
+	static constexpr auto DELAY_US = calcClockDelay();
+
+	static inline std::uint8_t disableInterrupts()
+	{
+		const auto oldInterruptState = SREG;
+		cli();
+		return oldInterruptState;
+	}
+
+	static inline void enableInterrupts(const std::uint8_t oldInterruptState)
+	{
+		SREG = oldInterruptState;
+	}
+};
+
+} // namespace spi

spi.hpp

@@ -2,30 +2,30 @@
 
 #include "config.hpp"
 #include "hardware.hpp"
+#include "software.hpp"
 
 #include "../io/io.hpp"
 
 namespace spi {
 
 template <class Driver>
-class Spi {
-  public:
-	static void init()
+struct Spi {
+	using word_t = typename Driver::word_t;
+
+	static inline void init()
 	{
 		Driver::init();
 	}
 
-	static uint8_t transfer(uint8_t ui8Data)
+	static inline word_t transfer(const word_t data)
 	{
-		return Driver::transfer(ui8Data);
+		return Driver::transfer(data);
 	}
 
-	static void select(bool bSelect)
+	static inline void select(const bool selectState)
 	{
-		Driver::select(bSelect);
+		Driver::select(selectState);
 	}
-
-  private:
 };
 
 } // namespace spi