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SAI MSB First Field

Question asked by Austin Wilhite on Oct 28, 2019
Latest reply on Nov 12, 2019 by Kerry Zhou

I was hoping someone could explain the effect of the SAI MSB First (MF) field on the receipt of data via I2S.


In this case, does MSB still stand for most significant byte (and not most significant bit)?


My interpretation is the following:

MSB First (MF) specifies if the first byte received per word is the most significant or least significant.



16-bit words

1111 0000 0000 1111 is shifted out, from left to right


With the MSB First (MF) set to 1 (selecting MSB):

The sample value is 0xF00F

the receive buffer (in our little-endian system) reads:

Base Address: 0x0F

Base Address + 1: 0xF0


With the LSB First (MF) set to 0 (selecting LSB):

The sample value is 0x0FF0

The receive buffer  (in our little-endian system) reads:

Base Address: 0xF0

Base Address + 1: 0x0F


Is this correct?