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Format For Data In 1772 Registers

Question asked by Christopher on Aug 1, 2013
Latest reply on Aug 1, 2013 by Christopher

Good day,

    I am trying to read data from a ADAU 1772's registers' through a C.O.M interface. I a mostly a high - level software person and am unfimilar

with the kind of data I that was presented (a binary/decimal (decimal number that could be equated to a binary which was the data that was suppose to be read) representation of a float (it may be a fixed point, I am still not sure, the poeple at work say it is a Q 5. 27 if it is a fixed point)). I asked some people at work about it who have had some experiance with the 1772 and they told me that

the data was being modified (other than converted to binary) before I got it through C.O.M. I had limited success with decrypting this data using the equations:

(For 1 Byte):

Positive Numbers:

DATA / 8

Negitive Numbers (data with a value above 120):

30 + ( ( -( DATA - 16 ) ) / 8 )

(For 4 Bytes):

Positive Numbers:

DATA / ( 8 ^ 9 )

Negitive Numbers (Integers):

( DATA / ( .5 * 8 ) ) / 2

Negitive Numbers (Rationals, Limited Success/Accuracy):

( DATA / ( 8 ^ 9 ) ) / 2

Some strange things I noticed were:
A: All odd 4 byte numbers come out to be the same value (-8^9)

B: Seemingly random 4 byte numbers are negitive

(what made some people at my work place say the data is being modified before it comes through C.O.M).

Does anyone know what format this data I am getting is in. I am going through a Genreal 2nd Order filter in SigmaStudio 3.8 to get it to the chip.