DownconverterFirmware/main.c

#include<avr/io.h>
#include "common.h"

String tosend="Test";

void Delay(uint32_t);
uint8_t SendReceiveSPIData(uint8_t);
void SendSPIDataADF4350 (uint32_t);

void spi_setup()
{
  // set direction of PB1 (DO) and PB2 (USCK) as output
  DDRB=(1<<PB1)|(1<<PB2);

  // set to three wire mode (SPI)
  USICR=(1<<USIWM0);          
  //USICR=(0<<USIWM1); not needed
}

int main()
{
  // set instructions to configure the ADF4350 settings for a 1 GHz +5dBm output
	uint32_t ar0=0x500000;
	uint32_t ar1=0x8008011;
	uint32_t ar2=0x4e42;
	uint32_t ar3=0x4b3;
	uint32_t ar4=0xac803c;
	uint32_t ar5=0x580005;

  spi_setup();
}

// general purpose delay
void Delay(uint32_t tmax)
{
	uint32_t i;
	for (i=0;i < tmax ; i++) 
		{
		asm("nop");
		}
}

// send an 8 bit word via SPI1 and receive an 8 bit word at the same time
uint8_t SendReceiveSPIData(uint8_t value)
{
	uint8_t lout = 0;
  short int i=0;
  
  for(i=0;i<=3;i++)
  {
    USIDR=value[i];         // write data bytes in Data register, will cause them to get sent on clock
    while(USIOIF==0)        // check USI data counter overflow flag to detect the end of transmission every byte
    {
      USICR|=(1<<USICLK)|(1<<USITC);  // enable clock for transmission and generate clock for slave deivce
    }
    USISR|=(1<<USIOIF)      // clear USI data counter overflow flag
  }

  // Read in a 16 bit frame (replace with proper reading response thing)
	///uint16_t inbyte = *(uint32_t *)(SPI1_BASE + 0x0c);
  while (lout == 0)
  {
    // do stuff to check response?
    lout = 1;

    // Read the SPI status register
		///uint32_t statusSPI = *(uint32_t *)(SPI1_BASE + 0x08);
		// Just bit 1 the transmit buffer empty flag - wait for this to go high then leave this function
		/// &= BIT_1;
		// The condition has been met so signal to get out of this loop
		///if (statusSPI == BIT_1) lout = 1;
  }
	return inbyte;
}

// send a 32 bit register value to the ADF4350
void SendSPIDataADF4350 (uint32_t outval)
{
  // split into 4 x 8-bit words
  uint8_t byte1 = (outval & 0xFF000000) >> 24;
  uint8_t byte2 = (outval & 0x00FF0000) >> 16;
  uint8_t byte3 = (outval & 0x0000FF00) >> 8;
  uint8_t byte4 = outval & 0x000000FF;

	// send these to the ADF4350 via SPI
	SendReceiveSPIData (byte1);
	SendReceiveSPIData (byte2);
  SendReceiveSPIData (byte3);
  SendReceiveSPIData (byte4);
	uint8_t lout = 0;
	// Loop waiting for the the SPI BSY flag to go low
	while (lout == 0)
	{
		// Read the SPI status register
		uint32_t statusSPI = *(uint32_t *)(SPI1_BASE + 0x08);
		// Just bit 7 the SPI BSY flag - wait for this to go low then leave this function
		statusSPI &= BIT_7;
		// The condition has been met so signal to get out of this loop
		if (statusSPI == 0) lout = 1;
	}
	// Add a delay here so the clock has gone low before LE is taken high
	Delay(10);
	// Take LE high to load the data into the register
	*(uint32_t *)(GPIOA_BASE + 0x10) = BIT_2;
	// Short delay while LE is high (minimum of 20ns)
	Delay(30);
	// Take LE low again
	*(uint32_t *)(GPIOA_BASE + 0x14) = BIT_2;
}