maziiz Posted September 15, 2019 Share Posted September 15, 2019 (edited) I am using pmod i2s2 and it is working fine with transmission data , Now I need to use it as a RX from an external mic I use this converter to use my normal headphone for both mic and speaker, and Iam trying to loop back the data I recorded , I use MCLK = 25 MHz , LRCLK = 48.8K hz , SCK = 3.128 Mhz (and these clocks are configurable) but I donot hear anything of the recording data. should I use an amplifier ? or should I configure anything else other than the clocks Pmod is operating as slave Edited September 15, 2019 by maziiz extra info Link to comment Share on other sites More sharing options...
0 artvvb Posted October 7, 2019 Share Posted October 7, 2019 Welcome to the forum! Those clocks should be fine. As mic hardware and line hardware are different, an amplifier is required. This why computers use two ports. The converter you linked only splits the cable, and does not appear to do any kind of amplification. Mic to line amplifiers are available for purchase online, but I do not have any specific ones to recommend. -Arthur Link to comment Share on other sites More sharing options...
0 engi Posted January 15, 2022 Share Posted January 15, 2022 (edited) On 9/15/2019 at 3:15 PM, maziiz said: I use MCLK = 25 MHz , LRCLK = 48.8K hz , SCK = 3.128 Mhz LR clock seems to be wrong. This should be the half i think, since it toggles with the 32 bits of a word indicating the same channel (L). for MCLK some devices requires 128xLR Clock, some 256x. For those reading the thread: I recommend to use an appropriate audio clock, which can be achieved with a PLL like this: PLL 1 : 100MHz -> 2:8 -> 25 MHz PLL 2: 25 MHz > 29/59 -> 12.288 MHz which is only some ppm away from the ideal frequency. The resulting Frequency should be : LR Clock 96kHz / MCLOCK 12.288 / 25.576 - Sample FR = 48.000.xx kHz Leaving PLL 1 away would be appropriate für 96kHz / 192kHz Audio. Edited December 7, 2022 by engi spelling Link to comment Share on other sites More sharing options...
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maziiz
I am using pmod i2s2 and it is working fine with transmission data ,
Now I need to use it as a RX from an external mic I use this converter to use my normal headphone for both mic and speaker,
and Iam trying to loop back the data I recorded , I use MCLK = 25 MHz , LRCLK = 48.8K hz , SCK = 3.128 Mhz (and these clocks are configurable)
but I donot hear anything of the recording data.
should I use an amplifier ?
or should I configure anything else other than the clocks
Pmod is operating as slave
Edited by maziizextra info
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