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eDMA with different source/destination data sizes

Question asked by Jason Valenzuela on Jan 19, 2016
Latest reply on Jan 20, 2016 by Earl Orlando Ramirez Sanchez

I have an application that requires a TDM8 stream to be transmitted using the I2S/SAI module. Said stream consists of eight channels of 16-bit audio. The receiver requires each TDM frame to be 32 bytes, or 256 bits, in length regardless of the actual data size. Using MSB-first transmission, each frame should begin with the MSB-LSB of the first channel, followed by 16 empty bits, then the MSB-LSB of the second channel, another 16 empty bits, and so on. To conserve memory, the source buffer within the Kinetis is an array of int16_t, so there is no padding between channels. Is it possible to configure the eDMA to read 16-bit data from the source, and write 32-bit data to the I2S TX FIFO?




Thank you,

Jason Valenzuela