Reorganising and adding lab2

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+/*************************************************************************************
+			       DEPARTMENT OF ELECTRICAL AND ELECTRONIC ENGINEERING
+					   		     IMPERIAL COLLEGE LONDON 
+
+ 				      EE 3.19: Real Time Digital Signal Processing
+					       Dr Paul Mitcheson and Daniel Harvey
+
+				        LAB 2: Learning C and Sinewave Generation 
+
+ 				             ********* S I N E . C **********
+
+             	Demonstrates outputing data from the DSK's audio port. 
+   			  Used for extending knowledge of C and using look up tables.
+
+ *************************************************************************************
+  				Updated for use on 6713 DSK by Danny Harvey: May-Aug 06/Dec 07/Oct 09
+				CCS V4 updates Sept 10
+ ************************************************************************************/
+/*
+ *  Initialy this example uses the AIC23 codec module of the 6713 DSK Board Support
+ *  Library to generate a 1KHz sine wave using a simple digital filter. 
+ *	You should modify the code to generate a sine of variable frequency.
+ */
+/**************************** Pre-processor statements ******************************/
+
+//  Included so program can make use of DSP/BIOS configuration tool.  
+#include "dsp_bios_cfg.h"
+
+/* The file dsk6713.h must be included in every program that uses the BSL.  This 
+   example also includes dsk6713_aic23.h because it uses the 
+   AIC23 codec module (audio interface). */
+#include "dsk6713.h"
+#include "dsk6713_aic23.h"
+
+// math library (trig functions)
+#include <math.h>
+
+// Some functions to help with configuring hardware
+#include "helper_functions_polling.h"
+
+
+// PI defined here for use in your code 
+#define PI 3.141592653589793
+
+// Contains the size of the sine table
+#define SINE_TABLE_SIZE 256
+
+
+
+/******************************* Global declarations ********************************/
+
+/* Audio port configuration settings: these values set registers in the AIC23 audio 
+   interface to configure it. See TI doc SLWS106D 3-3 to 3-10 for more info. */
+DSK6713_AIC23_Config Config = { \
+			 /**********************************************************************/
+			 /*   REGISTER	            FUNCTION			      SETTINGS         */ 
+			 /**********************************************************************/\
+    0x0017,  /* 0 LEFTINVOL  Left line input channel volume  0dB                   */\
+    0x0017,  /* 1 RIGHTINVOL Right line input channel volume 0dB                   */\
+    0x01f9,  /* 2 LEFTHPVOL  Left channel headphone volume   0dB                   */\
+    0x01f9,  /* 3 RIGHTHPVOL Right channel headphone volume  0dB                   */\
+    0x0011,  /* 4 ANAPATH    Analog audio path control       DAC on, Mic boost 20dB*/\
+    0x0000,  /* 5 DIGPATH    Digital audio path control      All Filters off       */\
+    0x0000,  /* 6 DPOWERDOWN Power down control              All Hardware on       */\
+    0x004f,  /* 7 DIGIF      Digital audio interface format  32 bit                */\
+    0x008d,  /* 8 SAMPLERATE Sample rate control             8 KHZ                 */\
+    0x0001   /* 9 DIGACT     Digital interface activation    On                    */\
+			 /**********************************************************************/
+};
+
+
+// Codec handle:- a variable used to identify audio interface  
+DSK6713_AIC23_CodecHandle H_Codec;
+
+/* Sampling frequency in HZ. Must only be set to 8000, 16000, 24000
+32000, 44100 (CD standard), 48000 or 96000  */ 
+int sampling_freq = 16000;
+
+
+// Array of data used by sinegen to generate sine. These are the initial values.                        
+float y[3] = {0,0,0};
+float x[1] = {1}; // impulse to start filter
+
+float a0 = 1.4142; // coefficients for difference equation
+float b0 = 0.707;
+
+// Holds the value of the current sample 
+float sample; 
+
+/* Left and right audio channel gain values, calculated to be less than signed 32 bit
+ maximum value. */
+Int32 L_Gain = 2100000000;
+Int32 R_Gain = 2100000000;
+
+
+/* Use this variable in your code to set the frequency of your sine wave 
+   be carefull that you do not set it above the current nyquist frequency! */
+float sine_freq = 1000.0;
+
+// Declares the global sine table that will be used to generate the sine wave
+float table[SINE_TABLE_SIZE];
+
+     
+/******************************* Function prototypes ********************************/
+void init_hardware(void);
+void sine_init(void);
+float sinegen(void);
+/********************************** Main routine ************************************/
+void main()
+{
+
+	// initialize board and the audio port
+	init_hardware();
+	
+	// Initialize the sine table
+	sine_init();
+	
+    // Loop endlessley generating a sine wave 
+    while(1)
+    {
+ 		// Calculate next sample
+ 		sample = sinegen();
+ 		
+     	/* Send a sample to the audio port if it is ready to transmit.
+           Note: DSK6713_AIC23_write() returns false if the port if is not ready */
+
+        //  send to LEFT channel (poll until ready)
+        while (!DSK6713_AIC23_write(H_Codec, ((Int32)(sample * L_Gain))))
+        {};
+		// send same sample to RIGHT channel (poll until ready)
+        while (!DSK6713_AIC23_write(H_Codec, ((Int32)(sample * R_Gain))))
+        {};
+        
+		// Set the sampling frequency. This function updates the frequency only if it 
+		// has changed. Frequency set must be one of the supported sampling freq.
+		set_samp_freq(&sampling_freq, Config, &H_Codec);
+	
+	}
+
+}
+
+/******************************* init_hardware() ************************************/
+void init_hardware()
+{
+    // Initialize the board support library, must be called first 
+    DSK6713_init();
+    
+    // Start the codec using the settings defined above in config 
+    H_Codec = DSK6713_AIC23_openCodec(0, &Config);
+
+	/* Defines number of bits in word used by MSBSP for communications with AIC23
+	 NOTE: this must match the bit resolution set in in the AIC23 */
+	MCBSP_FSETS(XCR1, XWDLEN1, 32BIT);
+	
+	/* Set the sampling frequency of the audio port. Must only be set to a supported 
+	   frequency (8000/16000/24000/32000/44100/48000/96000) */
+	
+	DSK6713_AIC23_setFreq(H_Codec, get_sampling_handle(&sampling_freq));
+
+}
+
+/******************************* init_hardware() ************************************/
+void sine_init()
+{
+	int i;
+	for(i = 0; i < SINE_TABLE_SIZE; i++)
+	{
+		table[i] = sin(2 * PI * i / SINE_TABLE_SIZE);
+	}
+}
+
+/********************************** sinegen() ***************************************/   
+float sinegen(void)
+{
+/*  This code produces a fixed sine of 1KHZ (if the sampling frequency is 8KHZ)
+    using a digital filter.
+ 	You will need to re-write this function to produce a sine of variable frequency
+ 	using a look up table instead of a filter.*/
+	
+	// temporary variable used to output values from function
+	float wave;
+
+	// represets the filter coeficients (square root of 2 and 1/square root of 2)
+	float a0 = 1.4142;
+	float b0 = 0.7071;
+
+	y[0] = a0 * y[1] - y[2] + b0 * x[0]; // Difference equation
+
+	y[2] = y[1]; // move values through buffer
+	y[1] = y[0];
+
+	x[0] = 0; // reset input to zero (to create the impulse) 
+
+	wave = y[0];
+
+    return(wave);
+    
+}
+
+
+