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Can I output unsigned integers from the ADS1247?

Question asked by Cat on Jul 25, 2012
Latest reply on Jul 25, 2012 by Cat

Hi,

I'm trying to simplify reading the ADS1247 and I thought that using the Offset registers might be an easy way to change the two's complement output into an unsigned output.

Table 12 on page 31 shows that setting the Offset Register to "8000000h" would get me a final output code of "7FFFFFh" with Vin = 0, which is, I think, what I want, but I have two problems:

 

1. "8000000h" is NOT a 24 bit number, it will not fit in 24 bits (or am I missing something?)

2. I assumed that's a typo and it means in fact "800000h". For some reason I still get negative numbers out of the ADC (MSbit is Hi on low values).

 

I know it's easy to post-process the two's complement after I get it out of the ADC; it's a challenge I want to solve now, to get it out straight unsigned :-)

 

Help, please?

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