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i2s full duplex DMA clarification

montagnanigiovanni
Associate II
Posted on May 30, 2015 at 09:09

hi everyone.

for my application i need to use two microphones with PDM output (left and right).

now i'm currently using one microphone, connected to a i2s in half duplex mode with DMA transfer (like the example inSTM32cube does) however, now i have to use also the second mycrophone, reading the datasheet i understood that i should connect it with sda_ext pin operating i2s in full duplex mode. now my memory written by DMA transfer will be filled in half the time right?

data order in the buffer will be 16 bits left channel-16 bit right channel (philips standard) and so on, right? 

thank you

Giovanni

1 REPLY 1
montagnanigiovanni
Associate II
Posted on June 01, 2015 at 07:45

maybe my question is not clear, i just wonder how will be packed my data from the two microphones in the memory. 16 bits one 16 bit the other, right?

there is a smart way to save these data in two different array, directly from DMA?

thank you

Giovanni