/*----------------------------------------------------------------------

	File:        Lms_c.c

	Description: Perform adaptive filtering on codec input.

		     Input: Right and left channels connected to the same source	

                     Output: Left channel  = original signal

	                     Right channel = filtered signal

 -----------------------------------------------------------------------*/

#include <stdio.h>

#include <string.h>

#include <common.h>

#include <codec.h>

#include <mcbspdrv.h>

#include <board.h>

#include <stdlib.h>

#include <timer.h>

#include <intr.h>

#include <regs.h>



#define SAMPLING_RATE 20000



extern int inicodec (int sampling_rate);



short h[8]={0,0,0,0,0,0,0,0};

short X[8]={0,0,0,0,0,0,0,0};

int Y=0;

int E=0;

	

#pragma CODE_SECTION (LMS_isr, ".iprog") 

interrupt void LMS_isr (void)

{

	int N=8;

    int i, temp;

	short BETA_E,D;

	int beta = 0x00000174; 



	temp = MCBSP0_DRR;    

	

	X[0] = (short) temp;

	D = X[0];

	

	Y=0;

	

	for(i=0;i<N;i++)

		Y = Y + ((_mpy(h[i],X[i])) << 1) ;

	

	E = D -(short) (Y>>16);

	BETA_E =(short)((_mpy(beta,E)) >>15);  

	

	for(i=N-1;i>=0;i--)

	{

		h[i] = h[i] +((_mpy(BETA_E,X[i])) >> 15);

		X[i]=X[i-1];

	}

	     

	MCBSP0_DXR = (temp &0xffff0000) |( ( (short)(Y>>16) )& 0x0000ffff);

	

	return;

}



void Init_Interrupts ()

{

	intr_reset();                     // Reset the interrupt system,

	                                  // disable all interrupts.

	INTR_CLR_FLAG (CPU_INT15);        // Clear previous interrupt request

	INTR_ENABLE (CPU_INT15);          // Enable cpu interrupt line 15

	intr_map(CPU_INT15,ISN_RINT0);    // Link receive interrupt of serial

	                                  // port 0 to interrupt line 15.

	intr_hook (LMS_isr,CPU_INT15);    // Assign the interrupt service routine

}



void main(void)

{

	evm_init();                        // Initialise EVM board.

	inicodec (SAMPLING_RATE);         // Initialise codec, adjust sampling rate.

	Init_Interrupts ();               // Initialise interrupts and hook isr.

	INTR_GLOBAL_ENABLE();             // Enable global interrupt.



	for (;;);                         // Main loop, does nothing.

}