#include <def21262.h>
#include "CS8416.h"
#include <SRU.h>

.global _init8416viaSPI;
.global _read_8416_register;


//===============================================================
.section/pm seg_pmco;


_init8416viaSPI:

	call _set8416_SPI_Params;

	r11=SPDIF_CTRL1;
	r12=0x00;
	call _write_8416_register;
	
	r11=SPDIF_CTRL2;
	r12=(GPO_NON_AUDIO);
	call _write_8416_register;
	
	r11=SPDIF_CTRL3;
	r12=(0xC0);
	call _write_8416_register;
	
	r11=SPDIF_CTRL4;
	r12=(0x81);
	call _write_8416_register;
	
	r11=SPDIF_DATA_FORMAT;
	r12=(FRMT_I2S);
	call _write_8416_register;
	
	r11=SPDIF_RX_ERR_MASK;
	r12=0x00;
	call _write_8416_register;
	
	r11=SPDIF_INT_MASK;
	r12=0x00;
	call _write_8416_register;
	
	r11=SPDIF_INT_MODE_MSB;
	r12=0x00;
	call _write_8416_register;
	
	r11=SPDIF_INT_MODE_LSB;
	r12=0x00;
	call _write_8416_register;
	
//	call _flush_SPI_FIFO;
	rts;

_init8416viaSPI.end:

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


_set8416_SPI_Params:
	
	//---------------------------------------------------------
	// Writing TXFLSH and RXFLSH bits in SPICTL clear the SPI
	// transmit and receive FIFOs, respectively.
	r0 = (TXFLSH | RXFLSH );
	dm(SPICTL)=r0;
	
	//----------------------------
	// Set the baud rate to 1 MHz
	r0 = 100;
	dm(SPIBAUD) = r0;
	
	//--------------------------------------------
	// Set the SPIFLG register to zero because the flag 
	//   pins are not used as the device select
	r0 = 0;
	dm(SPIFLG) = r0;
	
	//------------------------------------------------------
	// Now set the SPI control register 
	r0 = (SPIEN |   // enable the port
		  SPIMS |      // set SHARC as SPI master
		  MSBF |    // send MSB first
		  TIMOD1);  // Initialize SPI port to begin
	                  // transmitting when DMA is enabled 
	dm(SPICTL) = r0;
	rts;
	
_set8416_SPI_Params.end:

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

_flush_SPI_FIFO:

	// Clear the SPI receive and transmit shift registers
	r0 = (TXFLSH | RXFLSH );
	dm(SPICTL)=r0;
	rts;

_flush_SPI_FIFO.end:

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

_SPI_xfer_8416:

	// Word to transmit is passed in r8
	// Word send back from 8416 is returned in r8
	dm(TXSPI)=r8;
	
	// Wait until "SPI transfer complete" status bit 
	//   in SPISTAT (SPIF) indicates that we can send more
	do checkIfXferisDone until TF;
	    ustat3 = dm(SPISTAT);
	    BIT TST ustat3 SPIF;
	    checkIfXferisDone:
	      nop;
	    
	// Wait an extra 100 cycles to gate the clock down
	lcntr = 100, do pauseFor1835_xfer until lce;
	    pauseFor1835_xfer:
	    nop;
	    	    
	word_sent:
	nop;
	
	r8=dm(RXSPI);

	call _flush_SPI_FIFO;
	rts;
	
_SPI_xfer_8416.end:  


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

_read_8416_register:

	// Pass the address to read in r10, and the value is returned in r10

	// Initialize the SPI port
	call _set8416_SPI_Params;
	SRU(LOW,DAI_PB15_I);

	// Send the CS8416 ID indicating a write
	r0=SPDIF_WRITE_REG;
	call _SPI_xfer_8416;

	// Write the register address to the MAP
	r0=r10;
	call _SPI_xfer_8416;

	// Ignore the MAP's return value by gating the device select
	SRU(HIGH,DAI_PB15_I);
	lcntr = 100, do pauseFor1835_read until lce;
	    pauseFor1835_read:
	    nop;
	SRU(LOW,DAI_PB15_I);

	// Send the CS8416 ID indicating a read
	r0=SPDIF_READ_REG;
	call _SPI_xfer_8416;

	// Send a dummy value to clock the output
	r0=0;
	SRU(HIGH,DAI_PB15_I);

//	call _flush_SPI_FIFO;
	r10=dm(RXSPI);
	rts;

_read_8416_register.end:

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

_write_8416_register:

	// Pass the address to write in r11 and the value to write in r12

	SRU(LOW,DAI_PB15_I);

	r0=SPDIF_WRITE_REG;
	call _SPI_xfer_8416;

	r0=r11;
	call _SPI_xfer_8416;

	r0=r12;
	call _SPI_xfer_8416;
	
	SRU(HIGH,DAI_PB15_I);
	rts;
	
_write_8416_register.end: