1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
/*************************************************************************************
DEPARTMENT OF ELECTRICAL AND ELECTRONIC ENGINEERING
IMPERIAL COLLEGE LONDON
EE 3.19: Real Time Digital Signal Processing
Dr Paul Mitcheson and Daniel Harvey
LAB 3: Interrupt I/O
********* I N T I O. C **********
Demonstrates inputing and outputing data from the DSK's audio port using interrupts.
*************************************************************************************
Updated for use on 6713 DSK by Danny Harvey: May-Aug 2006
Updated for CCS V4 Sept 10
************************************************************************************/
/*
* You should modify the code so that interrupts are used to service the
* audio port.
*/
/**************************** Pre-processor statements ******************************/
#include <stdlib.h>
// 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 writing/reading the audio ports when using interrupts.
#include <helper_functions_ISR.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
// Table size
#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 */\
0x0043, /* 7 DIGIF Digital audio interface format 16 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 = 8000;
/* 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];
// Current index in the table, that can be used to calculate the next index
int sine_index = 0;
/******************************* Function prototypes ********************************/
void init_hardware(void);
void init_HWI(void);
float sinegen(void);
void ISR_AIC(void);
void sine_init(void);
/********************************** Main routine ************************************/
void main(){
// initialize board and the audio port
init_hardware();
// initialize the sine wave
sine_init();
/* initialize hardware interrupts */
init_HWI();
/* loop indefinitely, waiting for interrupts */
while(1) {};
}
/********************************** init_hardware() **********************************/
void init_hardware()
{
// Initialize the board support library, must be called first
DSK6713_init();
// Start the AIC23 codec using the settings defined above in config
H_Codec = DSK6713_AIC23_openCodec(0, &Config);
/* Function below sets the number of bits in word used by MSBSP (serial port) for
receives from AIC23 (audio port). We are using a 32 bit packet containing two
16 bit numbers hence 32BIT is set for receive */
MCBSP_FSETS(RCR1, RWDLEN1, 32BIT);
/* Configures interrupt to activate on each consecutive available 32 bits
from Audio port hence an interrupt is generated for each L & R sample pair */
MCBSP_FSETS(SPCR1, RINTM, FRM);
/* These commands do the same thing as above but applied to data transfers to
the audio port */
MCBSP_FSETS(XCR1, XWDLEN1, 32BIT);
MCBSP_FSETS(SPCR1, XINTM, FRM);
}
/********************************** init_HWI() **************************************/
void init_HWI()
{
IRQ_globalDisable(); // Globally disables interrupts
IRQ_nmiEnable(); // Enables the NMI interrupt (used by the debugger)
IRQ_map(IRQ_EVT_XINT1,4); // Maps an event to a physical interrupt
IRQ_enable(IRQ_EVT_XINT1); // Enables the event
IRQ_globalEnable(); // Globally enables interrupts
}
// populates the table with appropriate sine values
void sine_init()
{
int i;
for(i = 0; i < SINE_TABLE_SIZE; i++)
{
table[i] = sin(2 * PI * i / SINE_TABLE_SIZE);
}
}
// returns the sample according to the sampling frequency
float sinegen()
{
unsigned sample_index = sine_index * sine_freq * SINE_TABLE_SIZE / sampling_freq;
sample_index %= SINE_TABLE_SIZE;
sine_index++;
return table[sample_index];
}
/******************** INTERRUPT SERVICE ROUTINE ***********************/
void ISR_AIC()
{
// temporary variable used to output values from function
float wave_out, wave;
wave = sinegen();
wave_out = wave < 0 ? wave : -wave;
mono_write_16Bit((short)(wave_out*32767));
}
|
