10 bit ADC instead of 12 bit for more accuracy on F28027

[emailcausey 0]

I am using ADCINA7 (pin J5.3) to measure the voltage from a pressure sensor (after being amplified by an INA333). I have attached 3 pictures.

 

Picture #1: Y axis = voltage (mV), X axis = sample #.

Picture #2: Exponential fit of curve from Picture #1 (in excel)

Picture #3: Voltage (mV) after the exponential curve is subtracted 

 

I am noticing unexpected spikes that are most noticeable in Picture 3.

 

I wish that I had the option of increasing the gain of the INA333, but that is not possible with my application.

 

A former TI employee that I spoke with suggested that I use a 10 bit ADC instead of 12 bit ADC to prevent these spikes from occurring. At the time, this seemed like a great idea but, upon looking into it, I became uncertain if this is a possibility. Also, I am uncertain how to actually change the code so that it only uses a 10 bit ADC.

 

I would appreciate suggestions either to convert the 12 bit ADC to 10 bits or other ideas of how I might remove these spikes. 

 

Thanks for the info!