SERCOM.h

/*
  Copyright (c) 2014 Arduino.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library 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 Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#ifndef _SERCOM_CLASS_
#define _SERCOM_CLASS_

#include "sam.h"

// SAMD51 has configurable MAX_SPI, else use peripheral clock default.
// Update: changing MAX_SPI via compiler flags is DEPRECATED, because
// this affects ALL SPI peripherals including some that should NOT be
// changed (e.g. anything using SD card). Instead, use setClockSource().
// This is left here for compatibility w/interim MAX_SPI-dependent code:
#if defined(MAX_SPI)
  #define SERCOM_SPI_FREQ_REF (MAX_SPI * 2)
#else
  #define SERCOM_SPI_FREQ_REF 48000000ul
#endif
// Other SERCOM peripherals always use the 48 MHz clock
#define SERCOM_FREQ_REF       48000000ul
#define SERCOM_NVIC_PRIORITY  ((1<<__NVIC_PRIO_BITS) - 1)

typedef enum
{
	UART_EXT_CLOCK = 0,
	UART_INT_CLOCK = 0x1u
} SercomUartMode;

typedef enum
{
	SPI_SLAVE_OPERATION = 0x2u,
	SPI_MASTER_OPERATION = 0x3u
} SercomSpiMode;

typedef enum
{
	I2C_SLAVE_OPERATION = 0x4u,
	I2C_MASTER_OPERATION = 0x5u
} SercomI2CMode;

typedef enum
{
	SERCOM_EVEN_PARITY = 0,
	SERCOM_ODD_PARITY,
	SERCOM_NO_PARITY
} SercomParityMode;

typedef enum
{
	SERCOM_STOP_BIT_1 = 0,
	SERCOM_STOP_BITS_2
} SercomNumberStopBit;

typedef enum
{
	MSB_FIRST = 0,
	LSB_FIRST
} SercomDataOrder;

typedef enum
{
	UART_CHAR_SIZE_8_BITS = 0,
	UART_CHAR_SIZE_9_BITS,
	UART_CHAR_SIZE_5_BITS = 0x5u,
	UART_CHAR_SIZE_6_BITS,
	UART_CHAR_SIZE_7_BITS
} SercomUartCharSize;

typedef enum
{
	SERCOM_RX_PAD_0 = 0,
	SERCOM_RX_PAD_1,
	SERCOM_RX_PAD_2,
	SERCOM_RX_PAD_3
} SercomRXPad;

typedef enum
{
	UART_TX_PAD_0 = 0x0ul,  // Only for UART
	UART_TX_PAD_2 = 0x1ul,  // Only for UART
	UART_TX_RTS_CTS_PAD_0_2_3 = 0x2ul,  // Only for UART with TX on PAD0, RTS on PAD2 and CTS on PAD3
} SercomUartTXPad;

typedef enum
{
	SAMPLE_RATE_x16 = 0x1,  // Fractional
	SAMPLE_RATE_x8  = 0x3,  // Fractional
} SercomUartSampleRate;

typedef enum
{
	SERCOM_SPI_MODE_0 = 0, // CPOL : 0 | CPHA : 0
	SERCOM_SPI_MODE_1,     // CPOL : 0 | CPHA : 1
	SERCOM_SPI_MODE_2,     // CPOL : 1 | CPHA : 0
	SERCOM_SPI_MODE_3      // CPOL : 1 | CPHA : 1
} SercomSpiClockMode;

typedef enum
{
	SPI_PAD_0_SCK_1 = 0,
	SPI_PAD_2_SCK_3,
	SPI_PAD_3_SCK_1,
	SPI_PAD_0_SCK_3
} SercomSpiTXPad;

typedef enum
{
	SPI_CHAR_SIZE_8_BITS = 0x0ul,
	SPI_CHAR_SIZE_9_BITS
} SercomSpiCharSize;

typedef enum
{
	WIRE_UNKNOWN_STATE = 0x0ul,
	WIRE_IDLE_STATE,
	WIRE_OWNER_STATE,
	WIRE_BUSY_STATE
} SercomWireBusState;

typedef enum
{
	WIRE_WRITE_FLAG = 0x0ul,
	WIRE_READ_FLAG
} SercomWireReadWriteFlag;

typedef enum
{
	WIRE_MASTER_ACT_NO_ACTION = 0,
	WIRE_MASTER_ACT_REPEAT_START,
	WIRE_MASTER_ACT_READ,
	WIRE_MASTER_ACT_STOP
} SercomMasterCommandWire;

typedef enum
{
	WIRE_MASTER_ACK_ACTION = 0,
	WIRE_MASTER_NACK_ACTION
} SercomMasterAckActionWire;

// SERCOM clock source override is available only on SAMD51 (not 21)
// but the enumeration is made regardless so user code doesn't need
// ifdefs or lengthy comments explaining the different situations --
// the clock-sourcing functions just compile to nothing on SAMD21.
typedef enum {
  SERCOM_CLOCK_SOURCE_FCPU,     // F_CPU clock (GCLK0)
  SERCOM_CLOCK_SOURCE_48M,      // 48 MHz peripheral clock (GCLK1) (standard)
  SERCOM_CLOCK_SOURCE_100M,     // 100 MHz peripheral clock (GCLK2)
  SERCOM_CLOCK_SOURCE_32K,      // XOSC32K clock (GCLK3)
  SERCOM_CLOCK_SOURCE_12M,      // 12 MHz peripheral clock (GCLK4)
  SERCOM_CLOCK_SOURCE_NO_CHANGE // Leave clock source setting unchanged
} SercomClockSource;

class SERCOM
{
	public:
		SERCOM(Sercom* s) ;

		/* ========== UART ========== */
		void initUART(SercomUartMode mode, SercomUartSampleRate sampleRate, uint32_t baudrate=0) ;
		void initFrame(SercomUartCharSize charSize, SercomDataOrder dataOrder, SercomParityMode parityMode, SercomNumberStopBit nbStopBits) ;
		void initPads(SercomUartTXPad txPad, SercomRXPad rxPad) ;

		void resetUART( void ) ;
		void enableUART( void ) ;
		void flushUART( void ) ;
		void clearStatusUART( void ) ;
		bool availableDataUART( void ) ;
		bool isBufferOverflowErrorUART( void ) ;
		bool isFrameErrorUART( void ) ;
		void clearFrameErrorUART( void ) ;
		bool isParityErrorUART( void ) ;
		bool isDataRegisterEmptyUART( void ) ;
		uint8_t readDataUART( void ) ;
		int writeDataUART(uint8_t data) ;
		bool isUARTError() ;
		void acknowledgeUARTError() ;
		void enableDataRegisterEmptyInterruptUART();
		void disableDataRegisterEmptyInterruptUART();

		/* ========== SPI ========== */
		void initSPI(SercomSpiTXPad mosi, SercomRXPad miso, SercomSpiCharSize charSize, SercomDataOrder dataOrder) ;
		void initSPIClock(SercomSpiClockMode clockMode, uint32_t baudrate) ;
		void resetSPI( void ) ;
		void enableSPI( void ) ;
		void disableSPI( void ) ;
		void setDataOrderSPI(SercomDataOrder dataOrder) ;
		SercomDataOrder getDataOrderSPI( void ) ;
		void setBaudrateSPI(uint8_t divider) ;
		void setClockModeSPI(SercomSpiClockMode clockMode) ;
		uint8_t transferDataSPI(uint8_t data) ;
		bool isBufferOverflowErrorSPI( void ) ;
		bool isDataRegisterEmptySPI( void ) ;
		bool isTransmitCompleteSPI( void ) ;
		bool isReceiveCompleteSPI( void ) ;

		/* ========== WIRE ========== */
		void initSlaveWIRE(uint8_t address, bool enableGeneralCall = false) ;
		void initMasterWIRE(uint32_t baudrate) ;

		void resetWIRE( void ) ;
		void enableWIRE( void ) ;
    void disableWIRE( void );
    void prepareNackBitWIRE( void ) ;
    void prepareAckBitWIRE( void ) ;
    void prepareCommandBitsWire(uint8_t cmd);
		bool startTransmissionWIRE(uint8_t address, SercomWireReadWriteFlag flag) ;
		bool sendDataMasterWIRE(uint8_t data) ;
		bool sendDataSlaveWIRE(uint8_t data) ;
		bool isMasterWIRE( void ) ;
		bool isSlaveWIRE( void ) ;
		bool isBusIdleWIRE( void ) ;
		bool isBusOwnerWIRE( void ) ;
		bool isBusUnknownWIRE( void ) ;
		bool isArbLostWIRE( void );
		bool isBusBusyWIRE( void );
		bool isDataReadyWIRE( void ) ;
		bool isStopDetectedWIRE( void ) ;
		bool isRestartDetectedWIRE( void ) ;
		bool isAddressMatch( void ) ;
		bool isMasterReadOperationWIRE( void ) ;
    bool isRXNackReceivedWIRE( void ) ;
		int availableWIRE( void ) ;
		uint8_t readDataWIRE( void ) ;
		int8_t getSercomIndex(void);
#if defined(__SAMD51__)
		// SERCOM clock source override is only available on
		// SAMD51 (not 21) ... but these functions are declared
		// regardless so user code doesn't need ifdefs or lengthy
		// comments explaining the different situations -- these
		// just compile to nothing on SAMD21.
		void setClockSource(int8_t idx, SercomClockSource src, bool core);
		SercomClockSource getClockSource(void) { return clockSource; };
		uint32_t getFreqRef(void) { return freqRef; };
#else
		// The equivalent SAMD21 dummy functions...
		void setClockSource(int8_t idx, SercomClockSource src, bool core) { (void)idx; (void)src; (void)core; };
		SercomClockSource getClockSource(void) { return SERCOM_CLOCK_SOURCE_FCPU; };
		uint32_t getFreqRef(void) { return F_CPU; };
#endif

	private:
		Sercom* sercom;
#if defined(__SAMD51__)
                SercomClockSource clockSource;
                uint32_t freqRef; // Frequency corresponding to clockSource
#endif
		uint8_t calculateBaudrateSynchronous(uint32_t baudrate);
		uint32_t division(uint32_t dividend, uint32_t divisor) ;
		void initClockNVIC( void ) ;
};

#endif