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ADXL345 Data Format

Question asked by OU812 on Jan 23, 2013
Latest reply on Apr 27, 2016 by NevadaMark

Hello,

First post here so if I am doing this wrong my apologies.

I have an ADXL345 set up and it is communicating to my AVR through SPI just fine.  The issue is the data that is coming back.  According to the datasheet the data is returned as a two byte word from the respective DATAn 1/0 registers, which I am getting BUT.

 

The low byte is changing but the upper one (DATAX1) either comes back as 0x00, or 0xFF dictating +/- of center.  From the datasheet and quickstart guide I was understanding that in DATAX1 the upper nibble denotes positive or negative and the lower nibble contained the upper 2 or three bits of the reading.  I am using right justified format, and I am currently using 16g mode, but it seems to have the same issue on the other ranges.

 

I have also tried this with the FULL_RES bit set to 1 and 0 with no apparent change.

 

Any insight would be appreciated.

 

Oh one more thing.  I am programming in assembler, but I can read C in a limited capacity if it means anything.  I only mention this should a code example be posted.

 

Thank You

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