ESP8266lib/io/SoftSPI.h

#ifndef SOFTSPI_H
#define SOFTSPI_H

//#include "IO.h"
#include "fastGPIO.h"

// wemos D1 mini
#define SPI_CS_OUTPUT		GPIO15_OUTPUT_SET
#define SPI_MOSI_OUTPUT		GPIO13_OUTPUT_SET
#define SPI_MISO_INPUT		GPIO12_INPUT_SET
#define SPI_MISO_NO_PULLUP	GPIO12_INPUT_PULLUP_UNSET
#define SPI_CLK_OUTPUT		GPIO14_OUTPUT_SET

#define SPI_CS_LO			GPIO15_L
#define SPI_CS_HI			GPIO15_H

#define SPI_CLK_LO			GPIO14_L
#define SPI_CLK_HI			GPIO14_H

#define SPI_MOSI_LO			GPIO13_L
#define SPI_MOSI_HI			GPIO13_H

#define SPI_MISO_READ		GPIO12_IN

#define SPI_FAST

namespace spi {

	// MTDI 	GPIO12 	MISO (DIN)		D6
	// MTCK 	GPIO13 	MOSI (DOUT)		D7
	// MTMS 	GPIO14 	CLOCK			D5
	// MTDO 	GPIO15 	CS / SS			D8

//	#define PIN_CLK		14
//	#define PIN_MISO	12
//	#define PIN_MOSI	13

//	#define BIT(nr)		(1 << 0)

//public:

//	SoftSPI() {
//		// NOT CALLED!
//		// CALL INIT() manually!
//	}

	// THINGS THAT SHOULD RUN FAST AND THUS BE KEPT IN RAM

	static inline void csLo() { SPI_CS_LO; }				// D8
	static inline void csHi() { SPI_CS_HI; }				// D8

	static inline void clkLo() { SPI_CLK_LO; }				// D5
	static inline void clkHi() { SPI_CLK_HI; }				// D5

	static inline bool getMISO() {return SPI_MISO_READ;}	// D6

#ifdef SPI_FAST
	static inline void wait() {
		__asm__ __volatile__("nop");
	}
	static inline void waitLong() {
		os_delay_us(1);
	}
#else
	static inline void wait() {
		os_delay_us(2);
	}
	static inline void waitLong() {
		os_delay_us(50);
	}
#endif

	static void chipSelect() {
		clkLo();
		wait();
		csLo();
		waitLong();
	}

	static void chipDeselect() {
		clkLo();
		wait();
		csHi();
		wait();
	}

	static inline uint8_t readWriteBit(const bool out) {
		if(out) {SPI_MOSI_HI;} else {SPI_MOSI_LO;}
		wait();
		clkHi();
		wait();
		const bool inp = getMISO();
		wait();
		clkLo();
		wait();
		return (inp) ? 1 : 0;
	}

	/** write one bit to the bus */
	static inline void writeBit(const bool out) {
		if(out) {SPI_MOSI_HI;} else {SPI_MOSI_LO;}
		wait();
		clkHi();
		wait();
		clkLo();
		wait();
	}

	/** read one bit from the bus */
	static inline uint8_t readBit() {
		clkHi();
		wait();
		const bool val = getMISO();
		wait();
		clkLo();
		wait();
		return (val) ? 1 : 0;
	}



	// THINGS THAT MAY RUN SLOWER FROM THE FLASH



	static void ICACHE_FLASH_ATTR init() {
		SPI_MISO_INPUT;		SPI_MISO_NO_PULLUP; // D6: MISO
		SPI_MOSI_OUTPUT;						// D7: MOSI
		SPI_CLK_OUTPUT;							// D5: CLK
		SPI_CS_OUTPUT;							// D8: CS
	}


	/** read 16 bits */
	static uint16_t ICACHE_FLASH_ATTR readWord() {
		return
				(readBit() << 15) |
				(readBit() << 14) |
				(readBit() << 13) |
				(readBit() << 12) |
				(readBit() << 11) |
				(readBit() << 10) |
				(readBit() <<  9) |
				(readBit() <<  8) |
				(readBit() <<  7) |
				(readBit() <<  6) |
				(readBit() <<  5) |
				(readBit() <<  4) |
				(readBit() <<  3) |
				(readBit() <<  2) |
				(readBit() <<  1) |
				(readBit() <<  0);
	}

	/** read 8 bits */
	static uint8_t ICACHE_FLASH_ATTR readByte() {
		return
				(readBit() <<  7) |
				(readBit() <<  6) |
				(readBit() <<  5) |
				(readBit() <<  4) |
				(readBit() <<  3) |
				(readBit() <<  2) |
				(readBit() <<  1) |
				(readBit() <<  0);
	}



	static void ICACHE_FLASH_ATTR writeWord(const uint16_t word) {
			writeBit(word & BIT(15));
			writeBit(word & BIT(14));
			writeBit(word & BIT(13));
			writeBit(word & BIT(12));
			writeBit(word & BIT(11));
			writeBit(word & BIT(10));
			writeBit(word & BIT( 9));
			writeBit(word & BIT( 8));
			writeBit(word & BIT( 7));
			writeBit(word & BIT( 6));
			writeBit(word & BIT( 5));
			writeBit(word & BIT( 4));
			writeBit(word & BIT( 3));
			writeBit(word & BIT( 2));
			writeBit(word & BIT( 1));
			writeBit(word & BIT( 0));
	}

	static void ICACHE_FLASH_ATTR writeByte(const uint8_t byte) {
			writeBit(byte & BIT( 7));
			writeBit(byte & BIT( 6));
			writeBit(byte & BIT( 5));
			writeBit(byte & BIT( 4));
			writeBit(byte & BIT( 3));
			writeBit(byte & BIT( 2));
			writeBit(byte & BIT( 1));
			writeBit(byte & BIT( 0));
	}

	static uint16 ICACHE_FLASH_ATTR readWriteWord(const uint16_t word) {
		return
			(readWriteBit(word & BIT(15)) << 15) |
			(readWriteBit(word & BIT(14)) << 14) |
			(readWriteBit(word & BIT(13)) << 13) |
			(readWriteBit(word & BIT(12)) << 12) |
			(readWriteBit(word & BIT(11)) << 11) |
			(readWriteBit(word & BIT(10)) << 10) |
			(readWriteBit(word & BIT( 9)) <<  9) |
			(readWriteBit(word & BIT( 8)) <<  8) |
			(readWriteBit(word & BIT( 7)) <<  7) |
			(readWriteBit(word & BIT( 6)) <<  6) |
			(readWriteBit(word & BIT( 5)) <<  5) |
			(readWriteBit(word & BIT( 4)) <<  4) |
			(readWriteBit(word & BIT( 3)) <<  3) |
			(readWriteBit(word & BIT( 2)) <<  2) |
			(readWriteBit(word & BIT( 1)) <<  1) |
			(readWriteBit(word & BIT( 0)) <<  0);
	}

	static uint8 ICACHE_FLASH_ATTR readWriteByte(const uint8_t byte) {
		return
			(readWriteBit(byte & BIT( 7)) <<  7) |
			(readWriteBit(byte & BIT( 6)) <<  6) |
			(readWriteBit(byte & BIT( 5)) <<  5) |
			(readWriteBit(byte & BIT( 4)) <<  4) |
			(readWriteBit(byte & BIT( 3)) <<  3) |
			(readWriteBit(byte & BIT( 2)) <<  2) |
			(readWriteBit(byte & BIT( 1)) <<  1) |
			(readWriteBit(byte & BIT( 0)) <<  0);
	}

}


// create an instance ONCE
//SoftSPI spi;
//using spi = SoftSPI;


#endif // SOFTSPI_H