muneebziaa
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Hi experts,
I am using Xilnix Virtex 4 ml403 evaluation platform borad, I am using the on board audio processing IC LM4550, I have successfully acquired my audio signal through the on board audio input and output audio jack, but I am facing a problem and that is my audio signal is directly going to the output and I have found from a site that :
"The line-in volume (0x10) and microphone volume (0x0E) registers allow the line-level and microphone inputs to be fed directly into the output mixers, without digitizing these signals".
Link to the site:
https://www-mtl.mit.edu/Courses/6.111/labkit/audio.shtml
Datasheet say that when signal enter from the input jack either from line in or microphone, it first go to the built in18 bit ADC from where the 18 bit digital data goes in to the FPGA pin which follows the AC97 codec serial input protocol. after the digitized data is available at the FPGA pin (refered to SDATA_IN in the datasheet as output of digital from LM4550 ) user can save the data or can send the data back to the LM4550 IC through (SDATA_OUT pin refered in the datasheet for input of digital data) which also follows the AC97 codec serial protocol, this digitized data is send to the built in 18 bit DAC which send an analog signal to either line out jack or headphone jack.
I can control the input and output jack through code but I am still receiving my analog signal even I don't accept the digital data or send it back to the output pin.
My questions are
1. is it true that the line in and microphone is diectly connected to the output?
2. if not then how to stop my input signal to go to the output ports directly, because i am not sending the signal to the output in my code but I am still able to recive it at the output?
please anyone has any information about this please tell me.
Regards,
Muneeb ziaa
I am using Xilnix Virtex 4 ml403 evaluation platform borad, I am using the on board audio processing IC LM4550, I have successfully acquired my audio signal through the on board audio input and output audio jack, but I am facing a problem and that is my audio signal is directly going to the output and I have found from a site that :
"The line-in volume (0x10) and microphone volume (0x0E) registers allow the line-level and microphone inputs to be fed directly into the output mixers, without digitizing these signals".
Link to the site:
https://www-mtl.mit.edu/Courses/6.111/labkit/audio.shtml
Datasheet say that when signal enter from the input jack either from line in or microphone, it first go to the built in18 bit ADC from where the 18 bit digital data goes in to the FPGA pin which follows the AC97 codec serial input protocol. after the digitized data is available at the FPGA pin (refered to SDATA_IN in the datasheet as output of digital from LM4550 ) user can save the data or can send the data back to the LM4550 IC through (SDATA_OUT pin refered in the datasheet for input of digital data) which also follows the AC97 codec serial protocol, this digitized data is send to the built in 18 bit DAC which send an analog signal to either line out jack or headphone jack.
I can control the input and output jack through code but I am still receiving my analog signal even I don't accept the digital data or send it back to the output pin.
My questions are
1. is it true that the line in and microphone is diectly connected to the output?
2. if not then how to stop my input signal to go to the output ports directly, because i am not sending the signal to the output in my code but I am still able to recive it at the output?
please anyone has any information about this please tell me.
Regards,
Muneeb ziaa