//-----------------------------------------------------------------------------
#include "spi_master.h"

//-----------------------------------------------------------------------------
volatile U08 spi_clock_index;
volatile U08 spi_cpol;
volatile U08 spi_cpha;
volatile U08 spi_dord;
volatile BOOL spi_ss_active_high;
volatile U08 spi_read_buffer[SPI_READ_BUFFER_SIZE];
volatile U08 spi_write_buffer[SPI_WRITE_BUFFER_SIZE];

volatile U08 SPI_DEVICE_SS[2]={SPI_E_CS ,SPI_AD_CS};
volatile BOOL SPI_DEVICE_ACTIVE_HIGH[2]={false ,false};
//-----------------------------------------------------------------------------




void spi_init(void)
{
  // there are a total of 4 devices on the SPI bus:
	// 1.) Ethernet Modul WIZ812MJ 
	// 2.) AD7719 24bit ADC
	// 3.) LIS3LV accelerometer
	// 4.) MAX6662 temp sensor <---- not assembled!

	// We check if they all can live with the same SPI settings:
	// 1.) Ethernet modul:
	// supports spi mode=0 or mode=3 --> eighther cpol=cpha=0 or cpol=cpha=1
	//	THAT IS NOT TRUE!!!!
	// only mode 0 !!!!!!!!!!!!!!!!!!!!!!!!!!!1
	// MSB first
	// SCLK time 70ns minimum --> 14.2MHz maximum
	//
	// 2.) AD7719
	// supports mode=3 --> cpol=cpha=1
	// MSB first
	// SCLK time 200ns minimum --> 5MHz maximum
	//
	// 3.) LIS3LV
	// SPI CLK idles high 				--> cpol=1
	// data valid at rising edge. --> cpha=1 as well 
	// ==> mode 3 is supported only.
	// MSB first, but take take at multi byte transfers. LSbyte first
	// SCLK time - is not mentioned in the datasheet
	//
	// 4.) MAX6662 Tempsensor
	// since it is not assembled, this information is not necessary.

	// fastes SPI CLK frequency can be 					--> F_CPU/2 	= 4MHz
	// slowest can be 													--> F_CPU/128	= 62.5KHz
	
	// Lets try with the fastest!
	spi_clock_index = 0;  // Set Clockindex for lowest clock speed (F_CPU / 128)

  spi_dord = 0;					// Data Order MSB first dord = 0  --> good for all devices
  spi_cpol = 1;	spi_cpha = 1;					// SPI mode=3 			--> good for all devices
  spi_setup(); 					// Setup SPI bits and clock speed

}
//-----------------------------------------------------------------------------
void spi_setup(void)
{
  // Disable SPI, clear all flags
  SPCR = 0;

  // Set/Clear bits DORD, CPOL and CPHA in SPI Control Register
  spi_dord & 0x01 ? (SPCR |= (1 << DORD)) : (SPCR &= ~(1 << DORD));
  spi_cpol & 0x01 ? (SPCR |= (1 << CPOL)) : (SPCR &= ~(1 << CPOL));
  spi_cpha & 0x01 ? (SPCR |= (1 << CPHA)) : (SPCR &= ~(1 << CPHA));

  switch (spi_clock_index)
  {
    case 0:{ // F_CPU / 128
      SPCR |= (1 << SPR1) | (1 << SPR0);
      SPSR &= ~(1 <<SPI2X);
	  }
    break;

    case 1:{ // F_CPU / 64
      SPCR |= (1 << SPR1);
      SPSR &= ~(1 << SPI2X);
	  }
    break;

    case 2:{ // F_CPU / 32
      SPCR |= (1 << SPR1);
      SPSR |= (1 << SPI2X);
	  }
    break;

    case 3:{ // F_CPU / 16
      SPCR |= (1 << SPR0);
      SPSR &= ~(1 << SPI2X);
	  }
    break;

    case 4:{ // F_CPU / 8
      SPCR |= (1 << SPR0);
      SPSR |= (1 << SPI2X);
	  }
    break;

    case 5: // F_CPU / 4
      SPSR &= ~(1 << SPI2X);
    break;

    case 6: // F_CPU / 2
      SPSR |= (1 << SPI2X);
    break;

    default:{ // F_CPU / 128
      SPCR |= (1 << SPR1) | (1 << SPR0);
      SPSR &= ~(1 << SPI2X);
	  }
  }

  // Enable SPI in Master Mode
  SPCR |= (1 << SPE) | (1 << MSTR);
}

//-----------------------------------------------------------------------------

void spi_set_clock_index(U08 clock_index)
{
  if (clock_index > SPI_MAX_CLOCK_INDEX)
  {
    clock_index = SPI_MAX_CLOCK_INDEX;
  }

  spi_clock_index = clock_index;

  spi_setup(); // Setup SPI bits and clock speed
}
//-----------------------------------------------------------------------------

void spi_set_dord(U08 dord)
{
  if (dord > 1)
  {
    dord = 1;
  }

  spi_dord = dord;

  spi_setup(); // Setup SPI bits and clock speed
}
//-----------------------------------------------------------------------------

void spi_set_cpol(U08 cpol)
{
  if (cpol > 1)
  {
    cpol = 1;
  }

  spi_cpol = cpol;

  spi_setup(); // Setup SPI bits and clock speed
}
//-----------------------------------------------------------------------------

void spi_set_cpha(U08 cpha)
{
  if (cpha > 1)
  {
    cpha = 1;
  }

  spi_cpha = cpha;

  spi_setup(); // Setup SPI bits and clock speed
}

//-----------------------------------------------------------------------------

void spi_transfer(U08 bytes, U08 device)
{

  U08 n;
  // Transfer requested bytes
  for (n = 0; n < bytes; n++)
  {
  // Check for active slave select level
  if (SPI_DEVICE_ACTIVE_HIGH[device])
  {
		if (device == 0) {
    	PORTB |= (1 << SPI_DEVICE_SS[device]); // Set Slave Select high
		} else {
			PORTD |= (1 << SPI_DEVICE_SS[device]); // Set Slave Select high
		}
  }
  else
  {
		if (device == 0) {
    	PORTB &= ~(1 << SPI_DEVICE_SS[device]); // Set Slave Select low
		} else {
			PORTD &= ~(1 << SPI_DEVICE_SS[device]); // Set Slave Select low
		}
  }

  
    spi_read_buffer[n] = spi_transfer_byte(spi_write_buffer[n]);
  

  // Check for inactive slave select level
  if (SPI_DEVICE_ACTIVE_HIGH[device])
  {
		if (device == 0) {
    	PORTB &= ~(1 << SPI_DEVICE_SS[device]); // Set Slave Select low
		} else {
			PORTD &= ~(1 << SPI_DEVICE_SS[device]); // Set Slave Select low
		}
  }
  else
  {
		if (device == 0) {
    	PORTB |= (1 << SPI_DEVICE_SS[device]); // Set Slave Select high
		} else {
			PORTD |= (1 << SPI_DEVICE_SS[device]); // Set Slave Select high
		}
  }
  
  }
}
//-----------------------------------------------------------------------------

U08 spi_transfer_byte(U08 data)
{
  // Start SPI Transfer
	if (!(SPCR & (1<<MSTR)) )
		SPCR |= 1<<MSTR;
  SPDR = data;

  // Wait for transfer completed
  while (!(SPSR & (1 << SPIF)))
  {
  }

  // Return result of transfer
  return SPDR;
}

//-----------------------------------------------------------------------------
void spi_transfer_string(U08 length, U08* addr, U08 device)
{

  U08 n;
  
  // I assume the CS line is in "not enable"-state;
	if ( device == 0 ){
  	TGL_BIT(PORTB, SPI_DEVICE_SS[device]);  // I toggle the line
	} else {
		TGL_BIT(PORTD, SPI_DEVICE_SS[device]);  // I toggle the line
	}
  // now the line is in "enable"-state
  

  // Transfer requested bytes
  for (n = 0; n < length; n++)
  {
    spi_transfer_byte(addr[n]);
  }
	
		if ( device == 0 ){
  	TGL_BIT(PORTB, SPI_DEVICE_SS[device]);  // I toggle the line
	} else {
		TGL_BIT(PORTD, SPI_DEVICE_SS[device]);  // I toggle the line
	}

}
//-----------------------------------------------------------------------------