diff options
Diffstat (limited to 'lab3/RTDSP/intio.c')
| -rw-r--r-- | lab3/RTDSP/intio.c | 47 |
1 files changed, 16 insertions, 31 deletions
diff --git a/lab3/RTDSP/intio.c b/lab3/RTDSP/intio.c index b40299f..3c4ba02 100644 --- a/lab3/RTDSP/intio.c +++ b/lab3/RTDSP/intio.c @@ -43,6 +43,9 @@ // 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 @@ -71,23 +74,17 @@ 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; +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 = 2000.0; +float sine_freq = 1000.0; -// Contains the size of the sine table -#define SINE_TABLE_SIZE 256 // 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; -Int32 L_Gain = 2100000000; -Int32 R_Gain = 2100000000; -unsigned sine_phase_ind = 0; /******************************* Function prototypes ********************************/ void init_hardware(void); @@ -100,7 +97,9 @@ void main(){ // initialize board and the audio port init_hardware(); + // initialize the sine wave sine_init(); + /* initialize hardware interrupts */ init_HWI(); @@ -137,12 +136,12 @@ 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 + 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 +// populates the table with appropriate sine values void sine_init() { int i; @@ -152,37 +151,23 @@ void sine_init() } } -//Returns the sample according to the sampling frequency +// returns the sample according to the sampling frequency float sinegen() { - unsigned sample_index = sine_phase_ind * sine_freq * SINE_TABLE_SIZE / sampling_freq; - sample_index = sample_index % SINE_TABLE_SIZE; - sine_phase_ind++; + 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 ***********************/ - -/********************************** Ex2 ***************************************/ void ISR_AIC() { // temporary variable used to output values from function float wave_out, wave; - sine_phase_ind = sine_phase_ind % sampling_freq; + wave = sinegen(); wave_out = wave < 0 ? wave : -wave; mono_write_16Bit((short)(wave_out*32767)); } - - -/********************************** Ex1 ***************************************/ -/*void ISR_AIC() -{ - short mono_out, mono_in; - mono_in = mono_read_16Bit(); - mono_out = mono_in; //mono_in < 0 ? -mono_in : mono_in; - mono_write_16Bit(mono_out); -} -*/ - |