ADC read from ADS 7828 is not stable???

Hi all,

i am using ADS 7828e slave i2c ic with my arduino Micro to read analog signal.

i have issues!!

1) i am not getting stable value, when i am giving constant 3.3v.(deviation [u]+[/u] 40 is too high) 2) 12 bit adc not providing the values more than 3200 when i give 5v input. How can i get values till 4096

i have used both internal and external reference.but not working :neutral_face:

Thanks Alagappan

This chip seems to have it's own 2.5volt reference. So 0-2.5volt should give a value of 0-4095.

Is this chip mounted on a breakout board (link). How do you supply the Micro and this board. Post a diagram and/or picture of your setup/wiring. And the code (inside code tags). Leo..

Hi,

Thanks for reply

One question answered...

Hi Wawa,

which question was answered?

i tried with internal reference voltage , ext Vref = 0, Vdd = 5v. i gave. Yes it is going till 4095. but value is not constant when i gave constant 3.3v at ch0 analog pin.

Even at no signal at analog channel input, during initial reading it gives 0 value. when i try to read frequently it gives some decimal values like 30,40,..

but when i try to read with sufficient time interval between two adc.read i am getting 0v. i am confused much,...

Thanks