#include <def21369.h>
#include "ad1835.h"

.global _init1835viaSPI;


//===============================================================

.section/dm seg_dmda;

.var spi_semaphore;
.var config_tx_buf[]=          // Buffer of configuration data
            WR | DACCTRL1 | DACI2S | DAC24BIT | DACFS48,
            WR | DACCTRL2, // e.g.: | DACMUTE_R1 | DACMUTE_L2,
            WR | DACVOL_L1 | DACVOL_MAX,
            WR | DACVOL_R1 | DACVOL_MAX,
            WR | DACVOL_L2 | DACVOL_MAX,
            WR | DACVOL_R2 | DACVOL_MAX,
            WR | DACVOL_L3 | DACVOL_MAX,
            WR | DACVOL_R3 | DACVOL_MAX,
            WR | DACVOL_L4 | DACVOL_MAX,
            WR | DACVOL_R4 | DACVOL_MAX,
            WR | ADCCTRL1 | ADCFS48,
            WR | ADCCTRL2 | ADCI2S | ADC24BIT,
            WR | ADCCTRL3 | IMCLKx2 | PEAKRDEN;

//===============================================================

.section/pm seg_pmco;

_init1835viaSPI:

    //--------------------------
    // Clear SPTFLG and SPICTL regs to start
    r0 = 0;
    dm(SPICTL)=r0;
    dm(SPIFLG)=r0;

    //---------------------------------------------------------
    // Writing TXFLSH and RXFLSH bits in SPICTL clear the SPI
    // transmit and receive FIFOs, respectively.
    r0 = dm(SPICTL);
    r1 = (TXFLSH | RXFLSH );
    r0 = r0 OR r1;
    dm(SPICTL)=r0;


    //----------------------------
    // Setup the baud rate to 500 KHz
    r0 = 100;
    dm(SPIBAUD) = r0;


    //--------------------------------------------
    // Set the SPIFLG register to FLAG3 (0xF708)
    r0 = 0xF708;
    dm(SPIFLG) = r0;


    //------------------------------------------------------
    // Now set the SPI control register
    r0 = (SPIEN |   // enable the port
          SPIMS |   // set SHARC as SPI master
          MSBF |    // send MSB first
          WL16 |    // word length = 16 bits
          TIMOD1);  // Initialize SPI port to begin
                    // transmitting when DMA is enabled
    dm(SPICTL) = r0;


    //-------------------------------------------
    // Set up DAG registers to transmit via SPI
    i4 = config_tx_buf;
    m4 = 1;


    //------------------------------
    // Set up loop to transmit data
    lcntr = LENGTH(config_tx_buf), do word_sent until lce;

        // Send a word
        r0=dm(i4,m4);
        dm(TXSPI)=r0;

        // Wait until "SPI transfer complete" status bit
        //   in SPISTAT (SPIF) indicates that we can send more
        do checkIfTXisDone until TF;

            ustat3 = dm(SPISTAT);
            BIT TST ustat3 SPIF;

        checkIfTXisDone:
        nop;

        // Wait an extra 100 cycles to meet the timing
        //   requirements of the AD1835A
        lcntr = 100, do pauseFor1835 until lce;
        pauseFor1835:
        nop;


    word_sent:
    nop;

/*
    //-----------------------------------------
    // Flush SPI buffers after initialization
    //   You may want to do this before sending
    //   other SPI commands to guarantee that
    //   you have not accidentally left data in
    //   the transmit or receive FIFOs.
    r0 = dm(SPICTL);
    r1 = (TXFLSH | RXFLSH );
    r0 = r0 OR r1;
    dm(SPICTL)=r0;
*/

_init1835viaSPI.end:
    rts;