[AVR] Atmega644P interfacing CS5460A power meter

[Alex Aldridge Arabaolaza]

Hi mates. I'm really stuck trying to communicate both ATMega644P controller and a Cirrus Logic CS5460A power meter. I've read the datasheet carefully several times but I haven't been able to solve the problem yet. My problem is that the MISO line is always 0. I leave the code i use just in case you notice any kind of error.

Atmega644P is running @20Mhz while CS5460A is running @3.6864Mhz.

SPI initialization in ATMEGA644P:

/**
* Initialize and configure the SPI
* SPI Type: Master
* SPI Clock Rate: 1,25MHz
* SPI Clock Phase: Cycle Half
* SPI Clock Polarity: Low
* SPI Data Order: MSB First
*/
__C_task void InitSPI(void)
{
	SPCR0= (1<<SPE0) | (1<<MSTR0) | (1<<SPR00);
	SPSR0=0x00;
        SPI_initialized = TRUE;
}

Then I initialize the CS5460A by sending these commands:

void init_CS5460A_send_sequence(){
          
    CLRBIT(CS5460A_SS);                    //Enable CS5460A	
    for(int i = 0; i < 20000; i++);
    
    //Send Synchronization commands
    cs5460_sync();
    
    //soft reset
    cs5460_Write_data(CONFIG_REGISTER, 0x000080);

    //Resync
    cs5460_sync();
    
    //configure (x10 gain for current)
    cs5460_Write_data(CONFIG_REGISTER, 0x000061);
    
    //set integration period (72 clocks)
    cs5460_Write_data(CYCLE_COUNT_REGISTER, 0x000048);

    //reset all bits in status register (IC* bit ignored)
    cs5460_Write_data(STATUS_REGISTER, 0xFFFFFF);

    //set DRDY in mask register (for INT*)
    cs5460_Write_data(MASK_REGISTER, 0x800000);

    //start continuous computation cycles
    cs5460_send(0xE8);
    
    SETBIT(CS5460A_SS);                   //Disable CS5460A	
    for(int i = 0; i < 20000; i++);
}

And then, to retrieve data from CS5460A i use this code:

CLRBIT(CS5460A_SS);
      for(int i = 0; i < 20000; i++);
      cs5460_sync();
      cs5460_rst_st_reg();
      cs5460_Read_data(0x18);
      SETBIT(CS5460A_SS);
      for(int i = 0; i < 20000; i++);

I know the MISO line is always 0 as I looked carefully into it using an oscilloscope. The rest of the lines seem to be working fine. Do you have any idea about what can be going on?