Basic Audio Manipulation

ByHaitham Alogbi

Instructor: Dr.Kepuska

ECE3551 - Microcomputer System 1

Purpose

To use the blackfin processor BF-533 to implement what we have learned about the blackfin processor. My approach for this project by :

• Input Audio will play throw 4 speakers and all LEDs will be turned off.

• PF8(once) : activate the IIR low pass filter , LED: 4 turn on(twice) : activate the FIR low pass filter. LED :4, 5 turn on

• PF9 (once) : activate the IIR High pass filter. LED :4,5,6,7 turn on (twice) : activate the FIR High pass filter. LED:4,5,6,7,8,9 turn on

• PF10: Activate / Deactivate the Mute function. LED :4,5,6,7,8,9

•Input Audio will play throw 4 speakers and all LEDs will be turned off. EX_INTERRUPT_HANDLER(FlagA_ISR){ if (low==0 && high==0)

{

*pFlashA_PortB_Data=0x00;

iChannel0LeftIn = iRxBuffer1[INTERNAL_ADC_L0];iChannel0RightIn = iRxBuffer1[INTERNAL_ADC_R0];iChannel1LeftIn = iRxBuffer1[INTERNAL_ADC_L1];//liChannel1RightIn = iRxBuffer1[INTERNAL_ADC_R1];

Original();

iTxBuffer1[INTERNAL_DAC_L0] = iChannel0LeftOut;iTxBuffer1[INTERNAL_DAC_R0] = iChannel0RightOut;iTxBuffer1[INTERNAL_DAC_L1] = iChannel1LeftOut;iTxBuffer1[INTERNAL_DAC_R1] = iChannel1RightOut;

}}

Design Example IIR lowpass /High pass filter design•Transfer function for IIR filter.

•we implement the Transfer function using the two formulas:

•Matlab•Low pass filter frequencies : Fstop= 5000 Hz

Fpass = 8000 Hz

•High pass filter frequencies : Fstop= 1400 Hz Fc = 2000 Hz

•Generate a Header file which include the filter coefficients.

2

21

1

22

110

1

zAzA

zBzBBzH

mdBmdBmdBmy

mdAmdAmxmd

012

12

12

12

Problems I have faced while implementing the IIR low pass filter:

•Filter coefficient collapsed and corrupt every now and then since yesterday night.

Solutions:

•Redesign the filter in math lab and redo the coefficient. But it is not a permanent solution because the problem keeps coming back

pressing PF8(once): Activates IIR low pass filter.

EX_INTERRUPT_HANDLER(FlagA_ISR){if(*pFIO_FLAG_C == 0x0100)

{ *pFIO_FLAG_C = 0x0100; high=0;

if(low<2) {

low++; }

else {

low=0; }

}

}

EX_INTERRUPT_HANDLER(Sport0_RX_ISR){if(low==1)

{ high=0;

*pFlashA_PortB_Data=0x01;

iChannel0LeftIn = iRxBuffer1[INTERNAL_ADC_L0]; iChannel0RightIn = iRxBuffer1[INTERNAL_ADC_R0]; iChannel1LeftIn = iRxBuffer1[INTERNAL_ADC_L1]; iChannel1RightIn = iRxBuffer1[INTERNAL_ADC_R1];

lowpassfilterIIR();

iTxBuffer1[INTERNAL_DAC_L0] = iChannel0LeftOut; iTxBuffer1[INTERNAL_DAC_R0] = iChannel0RightOut; iTxBuffer1[INTERNAL_DAC_L1] = iChannel1LeftOut; iTxBuffer1[INTERNAL_DAC_R1] = iChannel1RightOut;

}}

PF8(once) continue:

pressing PF8(twice): Activates FIR low pass filter.EX_INTERRUPT_HANDLER(Sport0_RX_ISR){

if(low==2)

{high=0;

*pFlashA_PortB_Data=0x03;

iChannel0LeftIn = iRxBuffer1[INTERNAL_ADC_L0];iChannel0RightIn = iRxBuffer1[INTERNAL_ADC_R0];iChannel1LeftIn = iRxBuffer1[INTERNAL_ADC_L1];iChannel1RightIn = iRxBuffer1[INTERNAL_ADC_R1];

highpassfilter_FIR();

iTxBuffer1[INTERNAL_DAC_L0] = iChannel0LeftOut;iTxBuffer1[INTERNAL_DAC_R0] = iChannel0RightOut;iTxBuffer1[INTERNAL_DAC_L1] = iChannel1LeftOut;iTxBuffer1[INTERNAL_DAC_R1] = iChannel1RightOut;}

}

pressing PF9(ONCE): Activates IIR High pass filter.

EX_INTERRUPT_HANDLER(FlagA_ISR){if(*pFIO_FLAG_C == 0x0200)

{ *pFIO_FLAG_C = 0x0200; low=0;

if(high<2) {

high++; }

else {

high=0; }

}

}

EX_INTERRUPT_HANDLER(Sport0_RX_ISR){if(high==1)

{ low=0;

*pFlashA_PortB_Data=0x0f;

iChannel0LeftIn = iRxBuffer1[INTERNAL_ADC_L0]; iChannel0RightIn = iRxBuffer1[INTERNAL_ADC_R0]; iChannel1LeftIn = iRxBuffer1[INTERNAL_ADC_L1]; iChannel1RightIn = iRxBuffer1[INTERNAL_ADC_R1];

HighpassfilterIIR();

iTxBuffer1[INTERNAL_DAC_L0] = iChannel0LeftOut; iTxBuffer1[INTERNAL_DAC_R0] = iChannel0RightOut; iTxBuffer1[INTERNAL_DAC_L1] = iChannel1LeftOut; iTxBuffer1[INTERNAL_DAC_R1] = iChannel1RightOut;

}}

PF9 (once)continue:

pressing PF9(twice): Activates FIR High pass filter.EX_INTERRUPT_HANDLER(Sport0_RX_ISR){

if(high==2)//plays audio input through the high pass filter

{low = 0;

*pFlashA_PortB_Data=0x3f;

iChannel0LeftIn = iRxBuffer1[INTERNAL_ADC_L0];iChannel0RightIn = iRxBuffer1[INTERNAL_ADC_R0];iChannel1LeftIn = iRxBuffer1[INTERNAL_ADC_L1];iChannel1RightIn = iRxBuffer1[INTERNAL_ADC_R1];

lowpassfilter_FIR();

iTxBuffer1[INTERNAL_DAC_L0] = iChannel0LeftOut;iTxBuffer1[INTERNAL_DAC_R0] = iChannel0RightOut;iTxBuffer1[INTERNAL_DAC_L1] = iChannel1LeftOut;iTxBuffer1[INTERNAL_DAC_R1] = iChannel1RightOut;

}

}

pressing PF10: Activates Mute function.EX_INTERRUPT_HANDLER(FlagA_ISR){

*pFIO_FLAG_C = 0x0400; if(mute<1) {

mute++;

}else {

mute=0; }

}}EX_INTERRUPT_HANDLER(Sport0_RX_ISR){

if(mute==1)

{ high=0; low=0; mute_b(); }

}

conclusion

• I got all other filters to work as expected in in this class .

• I re-design the IIR low pass many times since yesterday night and it continues to

corrupt . Hopefully it will work during the demonstration.

•things I would change:

• If I have taken Signal and Systems I would be able to

improve my filter and how they sound.