LABVIEW Hi! I have built a microphone connected to my myDAQ and need help writin

Question

LABVIEW

Hi! I have built a microphone connected to my myDAQ and need help writing a LABView program that will do the following:

4. Triggered Recording: enable recording once a sound has been detected. You will need to determine what the triggerthreshold is and calibrate it for your system. In addition, you need to buffer data before the trigger so that theentire trigger event is captured in addition to recording sound after the trigger.

Explanation / Answer

// LABView program #include #include #include #include void playwav(char wavefile[14],float delaytime); struct WaveData { unsigned int SoundLength, Frequency; char *Sample; }; struct HeaderType { long RIFF; //RIFF header char NI1 [18]; //not important unsigned int Channels; //channels 1 = mono; 2 = stereo long Frequency; //sample frequency char NI2 [6]; //not important char BitRes; //bit resolution 8/16 bit char NI3 [12]; //not important } Header; struct WaveData Voice; //Pointer to wave file unsigned int Base; //Sound Blaster base address char WaveFile [25]; //File name for the wave file to be played /**************************************************************** ** Checks to see if a Sound Blaster exists at a given address, returns ** true if Sound Blaster found, false if not. ****************************************************************/ int ResetDSP(unsigned int Test) { //Reset the DSP outportb (Test + 0x6, 1); delay(10); outportb (Test + 0x6, 0); delay(10); //Check if reset was succesfull if ((inportb(Test + 0xE) & 0x80 == 0x80) && (inportb(Test + 0xA) == 0xAA)) { //DSP was found Base = Test; return (1); } else //No DSP was found return (0); } /**************************************************************** ** Send a byte to the DSP (Digital Signal Processor) on the Sound Blaster ** ****************************************************************/ void WriteDSP(unsigned char Value) { //Wait for the DSP to be ready to accept data while ((inportb(Base + 0xC) & 0x80) == 0x80); //Send byte outportb (Base + 0xC, Value); } /**************************************************************** ** Plays a part of the memory ** ****************************************************************/ void PlayBack (struct WaveData *Wave) { long LinearAddress; unsigned int Page, OffSet; unsigned char TimeConstant; TimeConstant = (65536 - (256000000 / Wave->Frequency)) >> 8; WriteDSP(0x40); //DSP-command 40h - Set sample frequency WriteDSP(TimeConstant); //Write time constant //Convert pointer to linear address LinearAddress = FP_SEG (Wave->Sample); LinearAddress = (LinearAddress Sample); Page = LinearAddress >> 16; //Calculate page OffSet = LinearAddress & 0xFFFF; //Calculate offset in the page /*Note - this procedure only works with DMA channel 1 */ outportb (0x0A, 5); //Mask DMA channel 1 outportb (0x0C, 0); //Clear byte pointer outportb (0x0B, 0x49); //Set mode /* The mode consists of the following: 0x49 = binary 01 00 10 01 | | | | | | | +- DMA channel 01 | | +---- Read operation (the DSP reads from memory) | +------- Single cycle mode +---------- Block mode */ outportb (0x02, OffSet & 0x100); //Write the offset to the DMA controller outportb (0x02, OffSet >> 8); outportb (0x83, Page); //Write the page to the DMA controller outportb (0x03, Wave->SoundLength & 0x100); outportb (0x03, Wave->SoundLength >> 8); outportb (0x0A, 1); //Unmask DMA channel WriteDSP(0x14); // DSP-command 14h - Single cycle playback WriteDSP(Wave->SoundLength & 0xFF); WriteDSP(Wave->SoundLength >> 8); } /**************************************************************** ** Loads a wave file into memory. ** ** This procedure expects a _very_ standard wave header. ** ** It doesn't perform much error checking. ** ****************************************************************/ int LoadVoice (struct WaveData *Voice, char *FileName) { FILE *WAVFile; //If it can't be opened... WAVFile = fopen(FileName, "rb"); if (WAVFile == NULL) { //..display error message return (0); } //Return length of file for sound length minus 48 bytes for .WAV header fseek(WAVFile, 0L, SEEK_END); Voice->SoundLength = ftell (WAVFile) - 48; fseek(WAVFile, 0L, SEEK_SET); //Check RIFF header if (Voice->SoundLength > 32000) { if (Voice->SoundLength > 64000) { Voice->SoundLength = 64000; } } free(Voice->Sample); Voice->Sample = (char *)malloc(Voice->SoundLength); //Assign memory if (!Voice->Sample) { return (0); } //Load the sample data fread(&Header, 46, 1, WAVFile); //Check RIFF header if (Header.RIFF != 0x46464952) { printf ("Not a wave file "); return (0); } //Check channels if (Header.Channels != 1) { printf ("Not a mono wave file "); return (0); } //Check bit resolution if (Header.BitRes != 8) { printf ("Not an 8-bit wave file "); return (0); } Voice->Frequency = Header.Frequency; //Load the sample data fread(Voice->Sample, Voice->SoundLength + 2, 1, WAVFile); fclose (WAVFile); //Close the file return (1); } void playwav (char wavefile[14], float delaytime = 1.0 ) { if (ResetDSP (0x220)) { //at 220h printf (""); } else { if (ResetDSP (0x240)) { //at 240h printf (""); } else { //or none at all printf (""); return; } } //Load wave file if (LoadVoice (&Voice, wavefile)) { //Start playback PlayBack (&Voice); delay(delaytime*1000); //Stops DMA-transfer WriteDSP (0xD0); } } int main() { playwav("c:\test.wav"); return 0; }

Related Questions

Navigate

• Browse (All)
• Browse L
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.