ADC resolution on the DEMOJM board

[johnpaul013]

I have an accelerometer attached to the ADC chip on my DEMOJM board.

The ADC chip can be set for 8, 10, or 12 bit resolution.

However, when I set it for 12-bit resolution, I only see 11 bit values.

I would expect  to see raw A/D counts go from 0 - 4095.

Instead, I see the counts go from 0 - 2047.

Anybody have any ideas?

Thanks.

[Betadine]

Hi John,

Im not an expert but I have been dealing with the JM DemoBoard and the ADC.

The first place where I would look -> initiliazing the ADC.

Take the datasheet and look for every flag in the init process.

Also take a look in the code (I get mad with the DemoJM Examples) but you will finally understand it by some way

Have you seen the voltages in the ADC pins? Make sure you have 5Vcc... ...  but as you say ...2047 is exactly the half of 4095, so I think that the hardware is not the problem.

I found some C examples from the internet "search for nikola" for this demoboard, using the ADC, not bad for understand how theADC works.

Hope it helps