teensy-spi/SPI.h

/*
 * Copyright (c) 2010 by Cristian Maglie <c.maglie@bug.st>
 * Copyright (c) 2014 by Paul Stoffregen <paul@pjrc.com> (Transaction API)
 * Copyright (c) 2014 by Matthijs Kooijman <matthijs@stdin.nl> (SPISettings AVR)
 * SPI Master library for arduino.
 *
 * This file is free software; you can redistribute it and/or modify
 * it under the terms of either the GNU General Public License version 2
 * or the GNU Lesser General Public License version 2.1, both as
 * published by the Free Software Foundation.
 */

#ifndef _SPI_H_INCLUDED
#define _SPI_H_INCLUDED

#include <Arduino.h>

#if defined(__arm__) && defined(TEENSYDUINO)
#if defined(__has_include) && __has_include(<EventResponder.h>)
// SPI_HAS_TRANSFER_ASYNC - Defined to say that the SPI supports an ASYNC version
// of the SPI_HAS_TRANSFER_BUF
#define SPI_HAS_TRANSFER_ASYNC 1
#include <DMAChannel.h>
#include <EventResponder.h>
#endif
#endif

// SPI_HAS_TRANSACTION means SPI has beginTransaction(), endTransaction(),
// usingInterrupt(), and SPISetting(clock, bitOrder, dataMode)
#define SPI_HAS_TRANSACTION 1

// Uncomment this line to add detection of mismatched begin/end transactions.
// A mismatch occurs if other libraries fail to use SPI.endTransaction() for
// each SPI.beginTransaction().  Connect a LED to this pin.  The LED will turn
// on if any mismatch is ever detected.
//#define SPI_TRANSACTION_MISMATCH_LED 5

// SPI_HAS_TRANSFER_BUF - is defined to signify that this library supports
// a version of transfer which allows you to pass in both TX and RX buffer
// pointers, either of which could be NULL
#define SPI_HAS_TRANSFER_BUF 1


#ifndef LSBFIRST
#define LSBFIRST 0
#endif
#ifndef MSBFIRST
#define MSBFIRST 1
#endif

#define SPI_MODE0 0x00
#define SPI_MODE1 0x04
#define SPI_MODE2 0x08
#define SPI_MODE3 0x0C

#define SPI_CLOCK_DIV4 0x00
#define SPI_CLOCK_DIV16 0x01
#define SPI_CLOCK_DIV64 0x02
#define SPI_CLOCK_DIV128 0x03
#define SPI_CLOCK_DIV2 0x04
#define SPI_CLOCK_DIV8 0x05
#define SPI_CLOCK_DIV32 0x06

#define SPI_MODE_MASK 0x0C  // CPOL = bit 3, CPHA = bit 2 on SPCR
#define SPI_CLOCK_MASK 0x03  // SPR1 = bit 1, SPR0 = bit 0 on SPCR
#define SPI_2XCLOCK_MASK 0x01  // SPI2X = bit 0 on SPSR


/**********************************************************/
/*     8 bit AVR-based boards				  */
/**********************************************************/

#if defined(__AVR__)

// define SPI_AVR_EIMSK for AVR boards with external interrupt pins
#if defined(EIMSK)
  #define SPI_AVR_EIMSK	 EIMSK
#elif defined(GICR)
  #define SPI_AVR_EIMSK	 GICR
#elif defined(GIMSK)
  #define SPI_AVR_EIMSK	 GIMSK
#endif

class SPISettings {
public:
	SPISettings(uint32_t clock, uint8_t bitOrder, uint8_t dataMode) {
		if (__builtin_constant_p(clock)) {
			init_AlwaysInline(clock, bitOrder, dataMode);
		} else {
			init_MightInline(clock, bitOrder, dataMode);
		}
	}
	SPISettings() {
		init_AlwaysInline(4000000, MSBFIRST, SPI_MODE0);
	}
private:
	void init_MightInline(uint32_t clock, uint8_t bitOrder, uint8_t dataMode) {
		init_AlwaysInline(clock, bitOrder, dataMode);
	}
	void init_AlwaysInline(uint32_t clock, uint8_t bitOrder, uint8_t dataMode)
	  __attribute__((__always_inline__)) {
		// Clock settings are defined as follows. Note that this shows SPI2X
		// inverted, so the bits form increasing numbers. Also note that
		// fosc/64 appears twice
		// SPR1 SPR0 ~SPI2X Freq
		//   0	  0	0   fosc/2
		//   0	  0	1   fosc/4
		//   0	  1	0   fosc/8
		//   0	  1	1   fosc/16
		//   1	  0	0   fosc/32
		//   1	  0	1   fosc/64
		//   1	  1	0   fosc/64
		//   1	  1	1   fosc/128

		// We find the fastest clock that is less than or equal to the
		// given clock rate. The clock divider that results in clock_setting
		// is 2 ^^ (clock_div + 1). If nothing is slow enough, we'll use the
		// slowest (128 == 2 ^^ 7, so clock_div = 6).
		uint8_t clockDiv;

		// When the clock is known at compiletime, use this if-then-else
		// cascade, which the compiler knows how to completely optimize
		// away. When clock is not known, use a loop instead, which generates
		// shorter code.
		if (__builtin_constant_p(clock)) {
			if (clock >= F_CPU / 2) {
				clockDiv = 0;
			} else if (clock >= F_CPU / 4) {
				clockDiv = 1;
			} else if (clock >= F_CPU / 8) {
				clockDiv = 2;
			} else if (clock >= F_CPU / 16) {
				clockDiv = 3;
			} else if (clock >= F_CPU / 32) {
				clockDiv = 4;
			} else if (clock >= F_CPU / 64) {
				clockDiv = 5;
			} else {
				clockDiv = 6;
			}
		} else {
			uint32_t clockSetting = F_CPU / 2;
			clockDiv = 0;
			while (clockDiv < 6 && clock < clockSetting) {
				clockSetting /= 2;
				clockDiv++;
			}
		}

		// Compensate for the duplicate fosc/64
		if (clockDiv == 6)
		clockDiv = 7;

		// Invert the SPI2X bit
		clockDiv ^= 0x1;

		// Pack into the SPISettings class
		spcr = _BV(SPE) | _BV(MSTR) | ((bitOrder == LSBFIRST) ? _BV(DORD) : 0) |
			(dataMode & SPI_MODE_MASK) | ((clockDiv >> 1) & SPI_CLOCK_MASK);
		spsr = clockDiv & SPI_2XCLOCK_MASK;
	}
	uint8_t spcr;
	uint8_t spsr;
	friend class SPIClass;
};



class SPIClass { // AVR
public:
	// Initialize the SPI library
	static void begin();

	// If SPI is used from within an interrupt, this function registers
	// that interrupt with the SPI library, so beginTransaction() can
	// prevent conflicts.  The input interruptNumber is the number used
	// with attachInterrupt.  If SPI is used from a different interrupt
	// (eg, a timer), interruptNumber should be 255.
	static void usingInterrupt(uint8_t interruptNumber);

	// Before using SPI.transfer() or asserting chip select pins,
	// this function is used to gain exclusive access to the SPI bus
	// and configure the correct settings.
	inline static void beginTransaction(SPISettings settings) {
		if (interruptMode > 0) {
			#ifdef SPI_AVR_EIMSK
			if (interruptMode == 1) {
				interruptSave = SPI_AVR_EIMSK;
				SPI_AVR_EIMSK &= ~interruptMask;
			} else
			#endif
			{
				uint8_t tmp = SREG;
				cli();
				interruptSave = tmp;
			}
		}
		#ifdef SPI_TRANSACTION_MISMATCH_LED
		if (inTransactionFlag) {
			pinMode(SPI_TRANSACTION_MISMATCH_LED, OUTPUT);
			digitalWrite(SPI_TRANSACTION_MISMATCH_LED, HIGH);
		}
		inTransactionFlag = 1;
		#endif
		SPCR = settings.spcr;
		SPSR = settings.spsr;
	}

	// Write to the SPI bus (MOSI pin) and also receive (MISO pin)
	inline static uint8_t transfer(uint8_t data) {
		SPDR = data;
		asm volatile("nop");
		while (!(SPSR & _BV(SPIF))) ; // wait
		return SPDR;
	}
	inline static uint16_t transfer16(uint16_t data) {
		union { uint16_t val; struct { uint8_t lsb; uint8_t msb; }; } in, out;
		in.val = data;
		if ((SPCR & _BV(DORD))) {
			SPDR = in.lsb;
			asm volatile("nop");
			while (!(SPSR & _BV(SPIF))) ;
			out.lsb = SPDR;
			SPDR = in.msb;
			asm volatile("nop");
			while (!(SPSR & _BV(SPIF))) ;
			out.msb = SPDR;
		} else {
			SPDR = in.msb;
			asm volatile("nop");
			while (!(SPSR & _BV(SPIF))) ;
			out.msb = SPDR;
			SPDR = in.lsb;
			asm volatile("nop");
			while (!(SPSR & _BV(SPIF))) ;
			out.lsb = SPDR;
		}
		return out.val;
	}
	inline static void transfer(void *buf, size_t count) {
		if (count == 0) return;
		uint8_t *p = (uint8_t *)buf;
		SPDR = *p;
		while (--count > 0) {
			uint8_t out = *(p + 1);
			while (!(SPSR & _BV(SPIF))) ;
			uint8_t in = SPDR;
			SPDR = out;
			*p++ = in;
		}
		while (!(SPSR & _BV(SPIF))) ;
		*p = SPDR;
	}
	static void setTransferWriteFill(uint8_t ch ) {_transferWriteFill = ch;}
	static void transfer(const void * buf, void * retbuf, uint32_t count);

	// After performing a group of transfers and releasing the chip select
	// signal, this function allows others to access the SPI bus
	inline static void endTransaction(void) {
		#ifdef SPI_TRANSACTION_MISMATCH_LED
		if (!inTransactionFlag) {
			pinMode(SPI_TRANSACTION_MISMATCH_LED, OUTPUT);
			digitalWrite(SPI_TRANSACTION_MISMATCH_LED, HIGH);
		}
		inTransactionFlag = 0;
		#endif
		if (interruptMode > 0) {
			#ifdef SPI_AVR_EIMSK
			if (interruptMode == 1) {
				SPI_AVR_EIMSK = interruptSave;
			} else
			#endif
			{
				SREG = interruptSave;
			}
		}
	}

	// Disable the SPI bus
	static void end();

	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	inline static void setBitOrder(uint8_t bitOrder) {
		if (bitOrder == LSBFIRST) SPCR |= _BV(DORD);
		else SPCR &= ~(_BV(DORD));
	}
	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	inline static void setDataMode(uint8_t dataMode) {
		SPCR = (SPCR & ~SPI_MODE_MASK) | dataMode;
	}
	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	inline static void setClockDivider(uint8_t clockDiv) {
		SPCR = (SPCR & ~SPI_CLOCK_MASK) | (clockDiv & SPI_CLOCK_MASK);
		SPSR = (SPSR & ~SPI_2XCLOCK_MASK) | ((clockDiv >> 2) & SPI_2XCLOCK_MASK);
	}
	// These undocumented functions should not be used.  SPI.transfer()
	// polls the hardware flag which is automatically cleared as the
	// AVR responds to SPI's interrupt
	inline static void attachInterrupt() { SPCR |= _BV(SPIE); }
	inline static void detachInterrupt() { SPCR &= ~_BV(SPIE); }

private:
	static uint8_t interruptMode; // 0=none, 1=mask, 2=global
	static uint8_t interruptMask; // which interrupts to mask
	static uint8_t interruptSave; // temp storage, to restore state
	#ifdef SPI_TRANSACTION_MISMATCH_LED
	static uint8_t inTransactionFlag;
	#endif
	static uint8_t _transferWriteFill;
};



/**********************************************************/
/*     32 bit Teensy 3.x				  */
/**********************************************************/

#elif defined(__arm__) && defined(TEENSYDUINO) && defined(KINETISK)

#define SPI_HAS_NOTUSINGINTERRUPT 1

class SPISettings {
public:
	SPISettings(uint32_t clock, uint8_t bitOrder, uint8_t dataMode) {
		if (__builtin_constant_p(clock)) {
			init_AlwaysInline(clock, bitOrder, dataMode);
		} else {
			init_MightInline(clock, bitOrder, dataMode);
		}
	}
	SPISettings() {
		init_AlwaysInline(4000000, MSBFIRST, SPI_MODE0);
	}
private:
	void init_MightInline(uint32_t clock, uint8_t bitOrder, uint8_t dataMode) {
		init_AlwaysInline(clock, bitOrder, dataMode);
	}
	void init_AlwaysInline(uint32_t clock, uint8_t bitOrder, uint8_t dataMode)
	  __attribute__((__always_inline__)) {
		uint32_t t, c = SPI_CTAR_FMSZ(7);
		if (bitOrder == LSBFIRST) c |= SPI_CTAR_LSBFE;
		if (__builtin_constant_p(clock)) {
			if	  (clock >= F_BUS / 2) {
				t = SPI_CTAR_PBR(0) | SPI_CTAR_BR(0) | SPI_CTAR_DBR
				  | SPI_CTAR_CSSCK(0);
			} else if (clock >= F_BUS / 3) {
				t = SPI_CTAR_PBR(1) | SPI_CTAR_BR(0) | SPI_CTAR_DBR
				  | SPI_CTAR_CSSCK(0);
			} else if (clock >= F_BUS / 4) {
				t = SPI_CTAR_PBR(0) | SPI_CTAR_BR(0) | SPI_CTAR_CSSCK(0);
			} else if (clock >= F_BUS / 5) {
				t = SPI_CTAR_PBR(2) | SPI_CTAR_BR(0) | SPI_CTAR_DBR
				  | SPI_CTAR_CSSCK(0);
			} else if (clock >= F_BUS / 6) {
				t = SPI_CTAR_PBR(1) | SPI_CTAR_BR(0) | SPI_CTAR_CSSCK(0);
			} else if (clock >= F_BUS / 8) {
				t = SPI_CTAR_PBR(0) | SPI_CTAR_BR(1) | SPI_CTAR_CSSCK(1);
			} else if (clock >= F_BUS / 10) {
				t = SPI_CTAR_PBR(2) | SPI_CTAR_BR(0) | SPI_CTAR_CSSCK(0);
			} else if (clock >= F_BUS / 12) {
				t = SPI_CTAR_PBR(1) | SPI_CTAR_BR(1) | SPI_CTAR_CSSCK(1);
			} else if (clock >= F_BUS / 16) {
				t = SPI_CTAR_PBR(0) | SPI_CTAR_BR(3) | SPI_CTAR_CSSCK(2);
			} else if (clock >= F_BUS / 20) {
				t = SPI_CTAR_PBR(2) | SPI_CTAR_BR(1) | SPI_CTAR_CSSCK(0);
			} else if (clock >= F_BUS / 24) {
				t = SPI_CTAR_PBR(1) | SPI_CTAR_BR(3) | SPI_CTAR_CSSCK(2);
			} else if (clock >= F_BUS / 32) {
				t = SPI_CTAR_PBR(0) | SPI_CTAR_BR(4) | SPI_CTAR_CSSCK(3);
			} else if (clock >= F_BUS / 40) {
				t = SPI_CTAR_PBR(2) | SPI_CTAR_BR(3) | SPI_CTAR_CSSCK(2);
			} else if (clock >= F_BUS / 56) {
				t = SPI_CTAR_PBR(3) | SPI_CTAR_BR(3) | SPI_CTAR_CSSCK(2);
			} else if (clock >= F_BUS / 64) {
				t = SPI_CTAR_PBR(0) | SPI_CTAR_BR(5) | SPI_CTAR_CSSCK(4);
			} else if (clock >= F_BUS / 96) {
				t = SPI_CTAR_PBR(1) | SPI_CTAR_BR(5) | SPI_CTAR_CSSCK(4);
			} else if (clock >= F_BUS / 128) {
				t = SPI_CTAR_PBR(0) | SPI_CTAR_BR(6) | SPI_CTAR_CSSCK(5);
			} else if (clock >= F_BUS / 192) {
				t = SPI_CTAR_PBR(1) | SPI_CTAR_BR(6) | SPI_CTAR_CSSCK(5);
			} else if (clock >= F_BUS / 256) {
				t = SPI_CTAR_PBR(0) | SPI_CTAR_BR(7) | SPI_CTAR_CSSCK(6);
			} else if (clock >= F_BUS / 384) {
				t = SPI_CTAR_PBR(1) | SPI_CTAR_BR(7) | SPI_CTAR_CSSCK(6);
			} else if (clock >= F_BUS / 512) {
				t = SPI_CTAR_PBR(0) | SPI_CTAR_BR(8) | SPI_CTAR_CSSCK(7);
			} else if (clock >= F_BUS / 640) {
				t = SPI_CTAR_PBR(2) | SPI_CTAR_BR(7) | SPI_CTAR_CSSCK(6);
			} else {	 /* F_BUS / 768 */
				t = SPI_CTAR_PBR(1) | SPI_CTAR_BR(8) | SPI_CTAR_CSSCK(7);
			}
		} else {
			for (uint32_t i=0; i<23; i++) {
				t = ctar_clock_table[i];
				if (clock >= F_BUS / ctar_div_table[i]) break;
			}
		}
		if (dataMode & 0x08) {
			c |= SPI_CTAR_CPOL;
		}
		if (dataMode & 0x04) {
			c |= SPI_CTAR_CPHA;
			t = (t & 0xFFFF0FFF) | ((t & 0xF000) >> 4);
		}
		ctar = c | t;
	}
	static const uint16_t ctar_div_table[23];
	static const uint32_t ctar_clock_table[23];
	uint32_t ctar;
	friend class SPIClass;
};



class SPIClass { // Teensy 3.x
public:
#if defined(__MK20DX128__) || defined(__MK20DX256__)
	static const uint8_t CNT_MISO_PINS = 2;
	static const uint8_t CNT_MOSI_PINS = 2;
	static const uint8_t CNT_SCK_PINS = 2;
	static const uint8_t CNT_CS_PINS = 9;
#elif defined(__MK64FX512__) || defined(__MK66FX1M0__)
	static const uint8_t CNT_MISO_PINS = 4;
	static const uint8_t CNT_MOSI_PINS = 4;
	static const uint8_t CNT_SCK_PINS = 3;
	static const uint8_t CNT_CS_PINS = 11;
#endif
	typedef struct {
		volatile uint32_t &clock_gate_register;
		uint32_t clock_gate_mask;
		uint8_t  queue_size;
		uint8_t  spi_irq;
		uint32_t max_dma_count;
		uint8_t  tx_dma_channel;
		uint8_t  rx_dma_channel;
		void     (*dma_rxisr)();
		uint8_t  miso_pin[CNT_MISO_PINS];
		uint32_t  miso_mux[CNT_MISO_PINS];
		uint8_t  mosi_pin[CNT_MOSI_PINS];
		uint32_t  mosi_mux[CNT_MOSI_PINS];
		uint8_t  sck_pin[CNT_SCK_PINS];
		uint32_t  sck_mux[CNT_SCK_PINS];
		uint8_t  cs_pin[CNT_CS_PINS];
		uint32_t  cs_mux[CNT_CS_PINS];
		uint8_t  cs_mask[CNT_CS_PINS];
	} SPI_Hardware_t;
	static const SPI_Hardware_t spi0_hardware;
	static const SPI_Hardware_t spi1_hardware;
	static const SPI_Hardware_t spi2_hardware;

	enum DMAState { notAllocated, idle, active, completed};
public:
	constexpr SPIClass(uintptr_t myport, uintptr_t myhardware)
		: port_addr(myport), hardware_addr(myhardware) {
	}
	// Initialize the SPI library
	void begin();

	// If SPI is to used from within an interrupt, this function registers
	// that interrupt with the SPI library, so beginTransaction() can
	// prevent conflicts.  The input interruptNumber is the number used
	// with attachInterrupt.  If SPI is used from a different interrupt
	// (eg, a timer), interruptNumber should be 255.
	void usingInterrupt(uint8_t n) {
		if (n == 3 || n == 4 || n == 24 || n == 33) {
			usingInterrupt(IRQ_PORTA);
		} else if (n == 0 || n == 1 || (n >= 16 && n <= 19) || n == 25 || n == 32) {
			usingInterrupt(IRQ_PORTB);
		} else if ((n >= 9 && n <= 13) || n == 15 || n == 22 || n == 23
		  || (n >= 27 && n <= 30)) {
			usingInterrupt(IRQ_PORTC);
		} else if (n == 2 || (n >= 5 && n <= 8) || n == 14 || n == 20 || n == 21) {
			usingInterrupt(IRQ_PORTD);
		} else if (n == 26 || n == 31) {
			usingInterrupt(IRQ_PORTE);
		}
	}
	void usingInterrupt(IRQ_NUMBER_t interruptName);
	void notUsingInterrupt(IRQ_NUMBER_t interruptName);

	// Before using SPI.transfer() or asserting chip select pins,
	// this function is used to gain exclusive access to the SPI bus
	// and configure the correct settings.
	void beginTransaction(SPISettings settings) {
		if (interruptMasksUsed) {
			__disable_irq();
			if (interruptMasksUsed & 0x01) {
				interruptSave[0] = NVIC_ICER0 & interruptMask[0];
				NVIC_ICER0 = interruptSave[0];
			}
			#if NVIC_NUM_INTERRUPTS > 32
			if (interruptMasksUsed & 0x02) {
				interruptSave[1] = NVIC_ICER1 & interruptMask[1];
				NVIC_ICER1 = interruptSave[1];
			}
			#endif
			#if NVIC_NUM_INTERRUPTS > 64 && defined(NVIC_ISER2)
			if (interruptMasksUsed & 0x04) {
				interruptSave[2] = NVIC_ICER2 & interruptMask[2];
				NVIC_ICER2 = interruptSave[2];
			}
			#endif
			#if NVIC_NUM_INTERRUPTS > 96 && defined(NVIC_ISER3)
			if (interruptMasksUsed & 0x08) {
				interruptSave[3] = NVIC_ICER3 & interruptMask[3];
				NVIC_ICER3 = interruptSave[3];
			}
			#endif
			__enable_irq();
		}
		#ifdef SPI_TRANSACTION_MISMATCH_LED
		if (inTransactionFlag) {
			pinMode(SPI_TRANSACTION_MISMATCH_LED, OUTPUT);
			digitalWrite(SPI_TRANSACTION_MISMATCH_LED, HIGH);
		}
		inTransactionFlag = 1;
		#endif
		if (port().CTAR0 != settings.ctar) {
			port().MCR = SPI_MCR_MDIS | SPI_MCR_HALT | SPI_MCR_PCSIS(0x3F);
			port().CTAR0 = settings.ctar;
			port().CTAR1 = settings.ctar| SPI_CTAR_FMSZ(8);
			port().MCR = SPI_MCR_MSTR | SPI_MCR_PCSIS(0x3F);
		}
	}

	// Write to the SPI bus (MOSI pin) and also receive (MISO pin)
	uint8_t transfer(uint8_t data) {
		port().SR = SPI_SR_TCF;
		port().PUSHR = data;
		while (!(port().SR & SPI_SR_TCF)) ; // wait
		return port().POPR;
	}
	uint16_t transfer16(uint16_t data) {
		port().SR = SPI_SR_TCF;
		port().PUSHR = data | SPI_PUSHR_CTAS(1);
		while (!(port().SR & SPI_SR_TCF)) ; // wait
		return port().POPR;
	}

	void inline transfer(void *buf, size_t count) {transfer(buf, buf, count);}
	void setTransferWriteFill(uint8_t ch ) {_transferWriteFill = ch;}
	void transfer(const void * buf, void * retbuf, size_t count);

	// Asynch support (DMA )
#ifdef SPI_HAS_TRANSFER_ASYNC
	bool transfer(const void *txBuffer, void *rxBuffer, size_t count,  EventResponderRef  event_responder);

	friend void _spi_dma_rxISR0(void);
	friend void _spi_dma_rxISR1(void);
	friend void _spi_dma_rxISR2(void);

	inline void dma_rxisr(void);
#endif


	// After performing a group of transfers and releasing the chip select
	// signal, this function allows others to access the SPI bus
	void endTransaction(void) {
		#ifdef SPI_TRANSACTION_MISMATCH_LED
		if (!inTransactionFlag) {
			pinMode(SPI_TRANSACTION_MISMATCH_LED, OUTPUT);
			digitalWrite(SPI_TRANSACTION_MISMATCH_LED, HIGH);
		}
		inTransactionFlag = 0;
		#endif
		if (interruptMasksUsed) {
			if (interruptMasksUsed & 0x01) {
				NVIC_ISER0 = interruptSave[0];
			}
			#if NVIC_NUM_INTERRUPTS > 32
			if (interruptMasksUsed & 0x02) {
				NVIC_ISER1 = interruptSave[1];
			}
			#endif
			#if NVIC_NUM_INTERRUPTS > 64 && defined(NVIC_ISER2)
			if (interruptMasksUsed & 0x04) {
				NVIC_ISER2 = interruptSave[2];
			}
			#endif
			#if NVIC_NUM_INTERRUPTS > 96 && defined(NVIC_ISER3)
			if (interruptMasksUsed & 0x08) {
				NVIC_ISER3 = interruptSave[3];
			}
			#endif
		}
	}

	// Disable the SPI bus
	void end();

	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	void setBitOrder(uint8_t bitOrder);

	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	void setDataMode(uint8_t dataMode);

	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	void setClockDivider(uint8_t clockDiv) {
		if (clockDiv == SPI_CLOCK_DIV2) {
			setClockDivider_noInline(SPISettings(12000000, MSBFIRST, SPI_MODE0).ctar);
		} else if (clockDiv == SPI_CLOCK_DIV4) {
			setClockDivider_noInline(SPISettings(4000000, MSBFIRST, SPI_MODE0).ctar);
		} else if (clockDiv == SPI_CLOCK_DIV8) {
			setClockDivider_noInline(SPISettings(2000000, MSBFIRST, SPI_MODE0).ctar);
		} else if (clockDiv == SPI_CLOCK_DIV16) {
			setClockDivider_noInline(SPISettings(1000000, MSBFIRST, SPI_MODE0).ctar);
		} else if (clockDiv == SPI_CLOCK_DIV32) {
			setClockDivider_noInline(SPISettings(500000, MSBFIRST, SPI_MODE0).ctar);
		} else if (clockDiv == SPI_CLOCK_DIV64) {
			setClockDivider_noInline(SPISettings(250000, MSBFIRST, SPI_MODE0).ctar);
		} else { /* clockDiv == SPI_CLOCK_DIV128 */
			setClockDivider_noInline(SPISettings(125000, MSBFIRST, SPI_MODE0).ctar);
		}
	}
	void setClockDivider_noInline(uint32_t clk);

	// These undocumented functions should not be used.  SPI.transfer()
	// polls the hardware flag which is automatically cleared as the
	// AVR responds to SPI's interrupt
	void attachInterrupt() { }
	void detachInterrupt() { }

	// Teensy 3.x can use alternate pins for these 3 SPI signals.
	void setMOSI(uint8_t pin);
	void setMISO(uint8_t pin);
	void setSCK(uint8_t pin);

	// return true if "pin" has special chip select capability
	uint8_t pinIsChipSelect(uint8_t pin);
	bool pinIsMOSI(uint8_t pin);
	bool pinIsMISO(uint8_t pin);
	bool pinIsSCK(uint8_t pin);
	// return true if both pin1 and pin2 have independent chip select capability
	bool pinIsChipSelect(uint8_t pin1, uint8_t pin2);
	// configure a pin for chip select and return its SPI_MCR_PCSIS bitmask
	// setCS() is a special function, not intended for use from normal Arduino
	// programs/sketches.  See the ILI3941_t3 library for an example.
	uint8_t setCS(uint8_t pin);

private:
	KINETISK_SPI_t & port() { return *(KINETISK_SPI_t *)port_addr; }
	const SPI_Hardware_t & hardware() { return *(const SPI_Hardware_t *)hardware_addr; }
	void updateCTAR(uint32_t ctar);
	uintptr_t port_addr;
	uintptr_t hardware_addr;
	uint8_t miso_pin_index = 0;
	uint8_t mosi_pin_index = 0;
	uint8_t sck_pin_index = 0;
	uint8_t interruptMasksUsed = 0;
	uint32_t interruptMask[(NVIC_NUM_INTERRUPTS+31)/32] = {};
	uint32_t interruptSave[(NVIC_NUM_INTERRUPTS+31)/32] = {};
	#ifdef SPI_TRANSACTION_MISMATCH_LED
	uint8_t inTransactionFlag = 0;
	#endif

	uint8_t _transferWriteFill = 0;

	// DMA Support
#ifdef SPI_HAS_TRANSFER_ASYNC
	bool initDMAChannels();
	DMAState     _dma_state = DMAState::notAllocated;
	uint32_t	_dma_count_remaining = 0;	// How many bytes left to output after current DMA completes
	DMAChannel   *_dmaTX = nullptr;
	DMAChannel    *_dmaRX = nullptr;
	EventResponder *_dma_event_responder = nullptr;
#endif
};



/**********************************************************/
/*     32 bit Teensy-LC					  */
/**********************************************************/

#elif defined(__arm__) && defined(TEENSYDUINO) && defined(KINETISL)

class SPISettings {
public:
	SPISettings(uint32_t clock, uint8_t bitOrder, uint8_t dataMode) {
		if (__builtin_constant_p(clock)) {
			init_AlwaysInline(clock, bitOrder, dataMode);
		} else {
			init_MightInline(clock, bitOrder, dataMode);
		}
	}
	SPISettings() {
		init_AlwaysInline(4000000, MSBFIRST, SPI_MODE0);
	}
private:
	void init_MightInline(uint32_t clock, uint8_t bitOrder, uint8_t dataMode) {
		init_AlwaysInline(clock, bitOrder, dataMode);
	}
	void init_AlwaysInline(uint32_t clock, uint8_t bitOrder, uint8_t dataMode)
	  __attribute__((__always_inline__)) {
		uint8_t c = SPI_C1_MSTR | SPI_C1_SPE;
		if (dataMode & 0x04) c |= SPI_C1_CPHA;
		if (dataMode & 0x08) c |= SPI_C1_CPOL;
		if (bitOrder == LSBFIRST) c |= SPI_C1_LSBFE;
		c1 = c;
		if (__builtin_constant_p(clock)) {
			  if	  (clock >= F_BUS /   2) { c = SPI_BR_SPPR(0) | SPI_BR_SPR(0);
			} else if (clock >= F_BUS /   4) { c = SPI_BR_SPPR(1) | SPI_BR_SPR(0);
			} else if (clock >= F_BUS /   6) { c = SPI_BR_SPPR(2) | SPI_BR_SPR(0);
			} else if (clock >= F_BUS /   8) { c = SPI_BR_SPPR(3) | SPI_BR_SPR(0);
			} else if (clock >= F_BUS /  10) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(0);
			} else if (clock >= F_BUS /  12) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(0);
			} else if (clock >= F_BUS /  14) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(0);
			} else if (clock >= F_BUS /  16) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(0);
			} else if (clock >= F_BUS /  20) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(1);
			} else if (clock >= F_BUS /  24) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(1);
			} else if (clock >= F_BUS /  28) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(1);
			} else if (clock >= F_BUS /  32) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(1);
			} else if (clock >= F_BUS /  40) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(2);
			} else if (clock >= F_BUS /  48) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(2);
			} else if (clock >= F_BUS /  56) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(2);
			} else if (clock >= F_BUS /  64) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(2);
			} else if (clock >= F_BUS /  80) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(3);
			} else if (clock >= F_BUS /  96) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(3);
			} else if (clock >= F_BUS / 112) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(3);
			} else if (clock >= F_BUS / 128) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(3);
			} else if (clock >= F_BUS / 160) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(4);
			} else if (clock >= F_BUS / 192) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(4);
			} else if (clock >= F_BUS / 224) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(4);
			} else if (clock >= F_BUS / 256) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(4);
			} else if (clock >= F_BUS / 320) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(5);
			} else if (clock >= F_BUS / 384) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(5);
			} else if (clock >= F_BUS / 448) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(5);
			} else if (clock >= F_BUS / 512) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(5);
			} else if (clock >= F_BUS / 640) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(6);
			} else      /* F_BUS / 768 */    { c = SPI_BR_SPPR(5) | SPI_BR_SPR(6);
			}
		} else {
			for (uint32_t i=0; i<30; i++) {
				c = br_clock_table[i];
				if (clock >= F_BUS / br_div_table[i]) break;
			}
		}
		br[0] = c;
		if (__builtin_constant_p(clock)) {
			  if	  (clock >= (F_PLL/2) /   2) { c = SPI_BR_SPPR(0) | SPI_BR_SPR(0);
			} else if (clock >= (F_PLL/2) /   4) { c = SPI_BR_SPPR(1) | SPI_BR_SPR(0);
			} else if (clock >= (F_PLL/2) /   6) { c = SPI_BR_SPPR(2) | SPI_BR_SPR(0);
			} else if (clock >= (F_PLL/2) /   8) { c = SPI_BR_SPPR(3) | SPI_BR_SPR(0);
			} else if (clock >= (F_PLL/2) /  10) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(0);
			} else if (clock >= (F_PLL/2) /  12) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(0);
			} else if (clock >= (F_PLL/2) /  14) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(0);
			} else if (clock >= (F_PLL/2) /  16) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(0);
			} else if (clock >= (F_PLL/2) /  20) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(1);
			} else if (clock >= (F_PLL/2) /  24) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(1);
			} else if (clock >= (F_PLL/2) /  28) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(1);
			} else if (clock >= (F_PLL/2) /  32) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(1);
			} else if (clock >= (F_PLL/2) /  40) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(2);
			} else if (clock >= (F_PLL/2) /  48) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(2);
			} else if (clock >= (F_PLL/2) /  56) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(2);
			} else if (clock >= (F_PLL/2) /  64) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(2);
			} else if (clock >= (F_PLL/2) /  80) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(3);
			} else if (clock >= (F_PLL/2) /  96) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(3);
			} else if (clock >= (F_PLL/2) / 112) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(3);
			} else if (clock >= (F_PLL/2) / 128) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(3);
			} else if (clock >= (F_PLL/2) / 160) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(4);
			} else if (clock >= (F_PLL/2) / 192) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(4);
			} else if (clock >= (F_PLL/2) / 224) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(4);
			} else if (clock >= (F_PLL/2) / 256) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(4);
			} else if (clock >= (F_PLL/2) / 320) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(5);
			} else if (clock >= (F_PLL/2) / 384) { c = SPI_BR_SPPR(5) | SPI_BR_SPR(5);
			} else if (clock >= (F_PLL/2) / 448) { c = SPI_BR_SPPR(6) | SPI_BR_SPR(5);
			} else if (clock >= (F_PLL/2) / 512) { c = SPI_BR_SPPR(7) | SPI_BR_SPR(5);
			} else if (clock >= (F_PLL/2) / 640) { c = SPI_BR_SPPR(4) | SPI_BR_SPR(6);
			} else      /* (F_PLL/2) / 768 */    { c = SPI_BR_SPPR(5) | SPI_BR_SPR(6);
			}
		} else {
			for (uint32_t i=0; i<30; i++) {
				c = br_clock_table[i];
				if (clock >= (F_PLL/2) / br_div_table[i]) break;
			}
		}
		br[1] = c;
	}
	static const uint8_t  br_clock_table[30];
	static const uint16_t br_div_table[30];
	uint8_t c1, br[2];
	friend class SPIClass;
};


class SPIClass { // Teensy-LC
public:
	static const uint8_t CNT_MISO_PINS = 2;
	static const uint8_t CNT_MMOSI_PINS = 2;
	static const uint8_t CNT_SCK_PINS = 2;
	static const uint8_t CNT_CS_PINS = 2;
	typedef struct {
		volatile uint32_t &clock_gate_register;
		uint32_t clock_gate_mask;
		uint8_t  br_index;
		uint8_t  tx_dma_channel;
		uint8_t  rx_dma_channel;
		void     (*dma_isr)();
		uint8_t  miso_pin[CNT_MISO_PINS];
		uint32_t  miso_mux[CNT_MISO_PINS];
		uint8_t  mosi_pin[CNT_MMOSI_PINS];
		uint32_t  mosi_mux[CNT_MMOSI_PINS];
		uint8_t  sck_pin[CNT_SCK_PINS];
		uint32_t  sck_mux[CNT_SCK_PINS];
		uint8_t  cs_pin[CNT_CS_PINS];
		uint32_t  cs_mux[CNT_CS_PINS];
		uint8_t  cs_mask[CNT_CS_PINS];
	} SPI_Hardware_t;
	static const SPI_Hardware_t spi0_hardware;
	static const SPI_Hardware_t spi1_hardware;
	enum DMAState { notAllocated, idle, active, completed};
public:
	constexpr SPIClass(uintptr_t myport, uintptr_t myhardware)
		: port_addr(myport), hardware_addr(myhardware) {
	}
	// Initialize the SPI library
	void begin();

	// If SPI is to used from within an interrupt, this function registers
	// that interrupt with the SPI library, so beginTransaction() can
	// prevent conflicts.  The input interruptNumber is the number used
	// with attachInterrupt.  If SPI is used from a different interrupt
	// (eg, a timer), interruptNumber should be 255.
	void usingInterrupt(uint8_t n) {
		if (n == 3 || n == 4) {
			usingInterrupt(IRQ_PORTA);
		} else if ((n >= 2 && n <= 15) || (n >= 20 && n <= 23)) {
			usingInterrupt(IRQ_PORTCD);
		}
	}
	void usingInterrupt(IRQ_NUMBER_t interruptName) {
		uint32_t n = (uint32_t)interruptName;
		if (n < NVIC_NUM_INTERRUPTS) interruptMask |= (1 << n);
	}
	void notUsingInterrupt(IRQ_NUMBER_t interruptName) {
		uint32_t n = (uint32_t)interruptName;
		if (n < NVIC_NUM_INTERRUPTS) interruptMask &= ~(1 << n);
	}

	// Before using SPI.transfer() or asserting chip select pins,
	// this function is used to gain exclusive access to the SPI bus
	// and configure the correct settings.
	void beginTransaction(SPISettings settings) {
		if (interruptMask) {
			__disable_irq();
			interruptSave = NVIC_ICER0 & interruptMask;
			NVIC_ICER0 = interruptSave;
			__enable_irq();
		}
		#ifdef SPI_TRANSACTION_MISMATCH_LED
		if (inTransactionFlag) {
			pinMode(SPI_TRANSACTION_MISMATCH_LED, OUTPUT);
			digitalWrite(SPI_TRANSACTION_MISMATCH_LED, HIGH);
		}
		inTransactionFlag = 1;
		#endif
		port().C1 = settings.c1;
		port().BR = settings.br[hardware().br_index];
	}

	// Write to the SPI bus (MOSI pin) and also receive (MISO pin)
	uint8_t transfer(uint8_t data) {
		port().DL = data;
		while (!(port().S & SPI_S_SPRF)) ; // wait
		return port().DL;
	}
	uint16_t transfer16(uint16_t data) {
		port().C2 = SPI_C2_SPIMODE;
		port().S;
		port().DL = data;
		port().DH = data >> 8;
		while (!(port().S & SPI_S_SPRF)) ; // wait
		uint16_t r = port().DL | (port().DH << 8);
		port().C2 = 0;
		port().S;
		return r;
	}
	void transfer(void *buf, size_t count) {
		if (count == 0) return;
		uint8_t *p = (uint8_t *)buf;
		while (!(port().S & SPI_S_SPTEF)) ; // wait
		port().DL = *p;
		while (--count > 0) {
			uint8_t out = *(p + 1);
			while (!(port().S & SPI_S_SPTEF)) ; // wait
			__disable_irq();
			port().DL = out;
			while (!(port().S & SPI_S_SPRF)) ; // wait
			uint8_t in = port().DL;
			__enable_irq();
			*p++ = in;
		}
		while (!(port().S & SPI_S_SPRF)) ; // wait
		*p = port().DL;
	}

	void setTransferWriteFill(uint8_t ch ) {_transferWriteFill = ch;}
	void transfer(const void * buf, void * retbuf, size_t count);

	// Asynch support (DMA )
#ifdef SPI_HAS_TRANSFER_ASYNC
	bool transfer(const void *txBuffer, void *rxBuffer, size_t count,  EventResponderRef  event_responder);

	friend void _spi_dma_rxISR0(void);
	friend void _spi_dma_rxISR1(void);
	inline void dma_isr(void);
#endif

	// After performing a group of transfers and releasing the chip select
	// signal, this function allows others to access the SPI bus
	void endTransaction(void) {
		#ifdef SPI_TRANSACTION_MISMATCH_LED
		if (!inTransactionFlag) {
			pinMode(SPI_TRANSACTION_MISMATCH_LED, OUTPUT);
			digitalWrite(SPI_TRANSACTION_MISMATCH_LED, HIGH);
		}
		inTransactionFlag = 0;
		#endif
		if (interruptMask) {
			NVIC_ISER0 = interruptSave;
		}
	}

	// Disable the SPI bus
	void end();

	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	void setBitOrder(uint8_t bitOrder) {
		uint8_t c = port().C1 | SPI_C1_SPE;
		if (bitOrder == LSBFIRST) c |= SPI_C1_LSBFE;
		else c &= ~SPI_C1_LSBFE;
		port().C1 = c;
	}

	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	void setDataMode(uint8_t dataMode) {
		uint8_t c = port().C1 | SPI_C1_SPE;
		if (dataMode & 0x04) c |= SPI_C1_CPHA;
		else c &= ~SPI_C1_CPHA;
		if (dataMode & 0x08) c |= SPI_C1_CPOL;
		else c &= ~SPI_C1_CPOL;
		port().C1 = c;
	}

	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	void setClockDivider(uint8_t clockDiv) {
		unsigned int i = hardware().br_index;
		if (clockDiv == SPI_CLOCK_DIV2) {
			port().BR = (SPISettings(12000000, MSBFIRST, SPI_MODE0).br[i]);
		} else if (clockDiv == SPI_CLOCK_DIV4) {
			port().BR = (SPISettings(4000000, MSBFIRST, SPI_MODE0).br[i]);
		} else if (clockDiv == SPI_CLOCK_DIV8) {
			port().BR = (SPISettings(2000000, MSBFIRST, SPI_MODE0).br[i]);
		} else if (clockDiv == SPI_CLOCK_DIV16) {
			port().BR = (SPISettings(1000000, MSBFIRST, SPI_MODE0).br[i]);
		} else if (clockDiv == SPI_CLOCK_DIV32) {
			port().BR = (SPISettings(500000, MSBFIRST, SPI_MODE0).br[i]);
		} else if (clockDiv == SPI_CLOCK_DIV64) {
			port().BR = (SPISettings(250000, MSBFIRST, SPI_MODE0).br[i]);
		} else { /* clockDiv == SPI_CLOCK_DIV128 */
			port().BR = (SPISettings(125000, MSBFIRST, SPI_MODE0).br[i]);
		}
	}

	// These undocumented functions should not be used.  SPI.transfer()
	// polls the hardware flag which is automatically cleared as the
	// AVR responds to SPI's interrupt
	void attachInterrupt() { }
	void detachInterrupt() { }

	// Teensy LC can use alternate pins for these 3 SPI signals.
	void setMOSI(uint8_t pin);
	void setMISO(uint8_t pin);
	void setSCK(uint8_t pin);
	// return true if "pin" has special chip select capability
	bool pinIsChipSelect(uint8_t pin);
	bool pinIsMOSI(uint8_t pin);
	bool pinIsMISO(uint8_t pin);
	bool pinIsSCK(uint8_t pin);
	// return true if both pin1 and pin2 have independent chip select capability
	bool pinIsChipSelect(uint8_t pin1, uint8_t pin2) { return false; }
	// configure a pin for chip select and return its SPI_MCR_PCSIS bitmask
	// setCS() is a special function, not intended for use from normal Arduino
	// programs/sketches.  See the ILI3941_t3 library for an example.
	uint8_t setCS(uint8_t pin);

private:
	KINETISL_SPI_t & port() { return *(KINETISL_SPI_t *)port_addr; }
	const SPI_Hardware_t & hardware() { return *(const SPI_Hardware_t *)hardware_addr; }
	uintptr_t port_addr;
	uintptr_t hardware_addr;
	uint32_t interruptMask = 0;
	uint32_t interruptSave = 0;
	uint8_t mosi_pin_index = 0;
	uint8_t miso_pin_index = 0;
	uint8_t sck_pin_index = 0;
	#ifdef SPI_TRANSACTION_MISMATCH_LED
	uint8_t inTransactionFlag = 0;
	#endif
	uint8_t _transferWriteFill = 0;
#ifdef SPI_HAS_TRANSFER_ASYNC
	// DMA Support
	bool initDMAChannels();

	DMAState _dma_state = DMAState::notAllocated;
	uint32_t _dma_count_remaining = 0;	// How many bytes left to output after current DMA completes
	DMAChannel *_dmaTX = nullptr;
	DMAChannel *_dmaRX = nullptr;
	EventResponder *_dma_event_responder = nullptr;
#endif
};



/**********************************************************/
/*     32 bit Teensy 4.x                                  */
/**********************************************************/

#elif defined(__arm__) && defined(TEENSYDUINO) && (defined(__IMXRT1052__) || defined(__IMXRT1062__))

//#include "debug/printf.h"

// TODO......
#undef SPI_HAS_TRANSFER_ASYNC

class SPISettings {
public:
	SPISettings(uint32_t clock, uint8_t bitOrder, uint8_t dataMode) {
		if (__builtin_constant_p(clock)) {
			init_AlwaysInline(clock, bitOrder, dataMode);
		} else {
			init_MightInline(clock, bitOrder, dataMode);
		}
	}
	SPISettings() {
		init_AlwaysInline(4000000, MSBFIRST, SPI_MODE0);
	}
private:
	void init_MightInline(uint32_t clock, uint8_t bitOrder, uint8_t dataMode) {
		init_AlwaysInline(clock, bitOrder, dataMode);
	}
	void init_AlwaysInline(uint32_t clock, uint8_t bitOrder, uint8_t dataMode)
	  __attribute__((__always_inline__)) {
		// TODO: make these implement settings - for now, just fixed config

		uint32_t d, div, clkhz = 528000000/7;  // LPSPI peripheral clock
		if (clock == 0) clock =1;
		d= clkhz/clock;
		if (d && clkhz/d > clock) d++;
		if (d > 257) d= 257;  // max div
		if (d > 2) {
			div = d-2;
		} else {
			div =0;
		}
		ccr = LPSPI_CCR_SCKDIV(div) | LPSPI_CCR_DBT(div/2);
		tcr = LPSPI_TCR_FRAMESZ(7);    // TCR has polarity and bit order too
	}
	uint32_t ccr; // clock config, pg 2660 (RT1050 ref, rev 2)
	uint32_t tcr; // transmit command, pg 2664 (RT1050 ref, rev 2)
	friend class SPIClass;
};

class SPIClass { // Teensy 4
public:
	static const uint8_t CNT_MISO_PINS = 1;
	static const uint8_t CNT_MOSI_PINS = 1;
	static const uint8_t CNT_SCK_PINS = 1;
	static const uint8_t CNT_CS_PINS = 1;
	typedef struct {
		volatile uint32_t &clock_gate_register;
		const uint32_t clock_gate_mask;
		const uint8_t  miso_pin[CNT_MISO_PINS];
		const uint32_t  miso_mux[CNT_MISO_PINS];
		const uint8_t  mosi_pin[CNT_MOSI_PINS];
		const uint32_t  mosi_mux[CNT_MOSI_PINS];
		const uint8_t  sck_pin[CNT_SCK_PINS];
		const uint32_t  sck_mux[CNT_SCK_PINS];
		const uint8_t  cs_pin[CNT_CS_PINS];
		const uint32_t  cs_mux[CNT_CS_PINS];
	} SPI_Hardware_t;

public:
	constexpr SPIClass(IMXRT_LPSPI_t *myport, const SPI_Hardware_t *myhardware)
		: port(myport), hardware(myhardware) {
	}
	// Initialize the SPI library
	void begin();

	// If SPI is to used from within an interrupt, this function registers
	// that interrupt with the SPI library, so beginTransaction() can
	// prevent conflicts.  The input interruptNumber is the number used
	// with attachInterrupt.  If SPI is used from a different interrupt
	// (eg, a timer), interruptNumber should be 255.
	/*void usingInterrupt(uint8_t n) {
		if (n == 3 || n == 4 || n == 24 || n == 33) {
			usingInterrupt(IRQ_PORTA);
		} else if (n == 0 || n == 1 || (n >= 16 && n <= 19) || n == 25 || n == 32) {
			usingInterrupt(IRQ_PORTB);
		} else if ((n >= 9 && n <= 13) || n == 15 || n == 22 || n == 23
		  || (n >= 27 && n <= 30)) {
			usingInterrupt(IRQ_PORTC);
		} else if (n == 2 || (n >= 5 && n <= 8) || n == 14 || n == 20 || n == 21) {
			usingInterrupt(IRQ_PORTD);
		} else if (n == 26 || n == 31) {
			usingInterrupt(IRQ_PORTE);
		}
	}*/
	void usingInterrupt(IRQ_NUMBER_t interruptName);
	void notUsingInterrupt(IRQ_NUMBER_t interruptName);

	// Before using SPI.transfer() or asserting chip select pins,
	// this function is used to gain exclusive access to the SPI bus
	// and configure the correct settings.
	void beginTransaction(SPISettings settings) {
		if (interruptMasksUsed) {
			__disable_irq();
			if (interruptMasksUsed & 0x01) {
				interruptSave[0] = NVIC_ICER0 & interruptMask[0];
				NVIC_ICER0 = interruptSave[0];
			}
			if (interruptMasksUsed & 0x02) {
				interruptSave[1] = NVIC_ICER1 & interruptMask[1];
				NVIC_ICER1 = interruptSave[1];
			}
			if (interruptMasksUsed & 0x04) {
				interruptSave[2] = NVIC_ICER2 & interruptMask[2];
				NVIC_ICER2 = interruptSave[2];
			}
			if (interruptMasksUsed & 0x08) {
				interruptSave[3] = NVIC_ICER3 & interruptMask[3];
				NVIC_ICER3 = interruptSave[3];
			}
			if (interruptMasksUsed & 0x10) {
				interruptSave[4] = NVIC_ICER4 & interruptMask[4];
				NVIC_ICER4 = interruptSave[4];
			}
			__enable_irq();
		}
		#ifdef SPI_TRANSACTION_MISMATCH_LED
		if (inTransactionFlag) {
			pinMode(SPI_TRANSACTION_MISMATCH_LED, OUTPUT);
			digitalWrite(SPI_TRANSACTION_MISMATCH_LED, HIGH);
		}
		inTransactionFlag = 1;
		#endif

		//printf("trans\n");
		port->CR = 0;
		port->CFGR1 = LPSPI_CFGR1_MASTER | LPSPI_CFGR1_SAMPLE;
		port->CCR = settings.ccr;
		port->TCR = settings.tcr;
		//port->CCR = LPSPI_CCR_SCKDIV(4);
		//port->TCR = LPSPI_TCR_FRAMESZ(7);
		port->CR = LPSPI_CR_MEN;
	}

	// Write to the SPI bus (MOSI pin) and also receive (MISO pin)
	uint8_t transfer(uint8_t data) {
		// TODO: check for space in fifo?
		port->TDR = data;
		while (1) {
			uint32_t fifo = (port->FSR >> 16) & 0x1F;
			if (fifo > 0) return port->RDR;
		}
		//port().SR = SPI_SR_TCF;
		//port().PUSHR = data;
		//while (!(port().SR & SPI_SR_TCF)) ; // wait
		//return port().POPR;
	}
	uint16_t transfer16(uint16_t data) {
		uint32_t tcr = port->TCR;
		port->TCR = (tcr & 0xfffff000) | LPSPI_TCR_FRAMESZ(15);  // turn on 16 bit mode 
		port->TDR = data;		// output 16 bit data.
		while ((port->RSR & LPSPI_RSR_RXEMPTY)) ;	// wait while the RSR fifo is empty...
		port->TCR = tcr;	// restore back
		return port->RDR;
	}

	void inline transfer(void *buf, size_t count) {transfer(buf, buf, count);}
	void setTransferWriteFill(uint8_t ch ) {_transferWriteFill = ch;}
	void transfer(const void * buf, void * retbuf, size_t count);

	// Asynch support (DMA )
#ifdef SPI_HAS_TRANSFER_ASYNC
	bool transfer(const void *txBuffer, void *rxBuffer, size_t count,  EventResponderRef  event_responder);

	friend void _spi_dma_rxISR0(void);
	friend void _spi_dma_rxISR1(void);
	friend void _spi_dma_rxISR2(void);

	inline void dma_rxisr(void);
#endif


	// After performing a group of transfers and releasing the chip select
	// signal, this function allows others to access the SPI bus
	void endTransaction(void) {
		#ifdef SPI_TRANSACTION_MISMATCH_LED
		if (!inTransactionFlag) {
			pinMode(SPI_TRANSACTION_MISMATCH_LED, OUTPUT);
			digitalWrite(SPI_TRANSACTION_MISMATCH_LED, HIGH);
		}
		inTransactionFlag = 0;
		#endif
		if (interruptMasksUsed) {
			if (interruptMasksUsed & 0x01) NVIC_ISER0 = interruptSave[0];
			if (interruptMasksUsed & 0x02) NVIC_ISER1 = interruptSave[1];
			if (interruptMasksUsed & 0x04) NVIC_ISER2 = interruptSave[2];
			if (interruptMasksUsed & 0x08) NVIC_ISER3 = interruptSave[3];
			if (interruptMasksUsed & 0x10) NVIC_ISER4 = interruptSave[4];
		}
	}

	// Disable the SPI bus
	void end();

	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	void setBitOrder(uint8_t bitOrder);

	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	void setDataMode(uint8_t dataMode);

	// This function is deprecated.	 New applications should use
	// beginTransaction() to configure SPI settings.
	void setClockDivider(uint8_t clockDiv) {
		if (clockDiv == SPI_CLOCK_DIV2) {
			//setClockDivider_noInline(SPISettings(12000000, MSBFIRST, SPI_MODE0).ctar);
		} else if (clockDiv == SPI_CLOCK_DIV4) {
			//setClockDivider_noInline(SPISettings(4000000, MSBFIRST, SPI_MODE0).ctar);
		} else if (clockDiv == SPI_CLOCK_DIV8) {
			//setClockDivider_noInline(SPISettings(2000000, MSBFIRST, SPI_MODE0).ctar);
		} else if (clockDiv == SPI_CLOCK_DIV16) {
			//setClockDivider_noInline(SPISettings(1000000, MSBFIRST, SPI_MODE0).ctar);
		} else if (clockDiv == SPI_CLOCK_DIV32) {
			//setClockDivider_noInline(SPISettings(500000, MSBFIRST, SPI_MODE0).ctar);
		} else if (clockDiv == SPI_CLOCK_DIV64) {
			//setClockDivider_noInline(SPISettings(250000, MSBFIRST, SPI_MODE0).ctar);
		} else { /* clockDiv == SPI_CLOCK_DIV128 */
			//setClockDivider_noInline(SPISettings(125000, MSBFIRST, SPI_MODE0).ctar);
		}
	}
	void setClockDivider_noInline(uint32_t clk);

	// These undocumented functions should not be used.  SPI.transfer()
	// polls the hardware flag which is automatically cleared as the
	// AVR responds to SPI's interrupt
	void attachInterrupt() { }
	void detachInterrupt() { }

	// Teensy 3.x can use alternate pins for these 3 SPI signals.
	void setMOSI(uint8_t pin);
	void setMISO(uint8_t pin);
	void setSCK(uint8_t pin);

	// return true if "pin" has special chip select capability
	uint8_t pinIsChipSelect(uint8_t pin);
	bool pinIsMOSI(uint8_t pin);
	bool pinIsMISO(uint8_t pin);
	bool pinIsSCK(uint8_t pin);
	// return true if both pin1 and pin2 have independent chip select capability
	bool pinIsChipSelect(uint8_t pin1, uint8_t pin2);
	// configure a pin for chip select and return its SPI_MCR_PCSIS bitmask
	// setCS() is a special function, not intended for use from normal Arduino
	// programs/sketches.  See the ILI3941_t3 library for an example.
	uint8_t setCS(uint8_t pin);

private:
	//KINETISK_SPI_t & port() { return *(KINETISK_SPI_t *)port_addr; }
	IMXRT_LPSPI_t * const port;
	const SPI_Hardware_t * const hardware;

	void updateCTAR(uint32_t ctar);
	uint8_t miso_pin_index = 0;
	uint8_t mosi_pin_index = 0;
	uint8_t sck_pin_index = 0;
	uint8_t interruptMasksUsed = 0;
	uint32_t interruptMask[(NVIC_NUM_INTERRUPTS+31)/32] = {};
	uint32_t interruptSave[(NVIC_NUM_INTERRUPTS+31)/32] = {};
	#ifdef SPI_TRANSACTION_MISMATCH_LED
	uint8_t inTransactionFlag = 0;
	#endif

	uint8_t _transferWriteFill = 0;

	// DMA Support
#ifdef SPI_HAS_TRANSFER_ASYNC
	bool initDMAChannels();
	DMAState     _dma_state = DMAState::notAllocated;
	uint32_t	_dma_count_remaining = 0;	// How many bytes left to output after current DMA completes
	DMAChannel   *_dmaTX = nullptr;
	DMAChannel    *_dmaRX = nullptr;
	EventResponder *_dma_event_responder = nullptr;
#endif
};










#endif



extern SPIClass SPI;
#if defined(__MKL26Z64__)
extern SPIClass SPI1;
#endif
#if defined(__MK64FX512__) || defined(__MK66FX1M0__)
extern SPIClass SPI1;
extern SPIClass SPI2;
#endif
#endif