ADC read from ADS 7828 is not stable???

Using Arduino Sensors
1

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 + 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

2

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..

3

Hi,

Thanks for reply

ads7828.png
ads7828.png768×499 94 KB

4

One question answered...

5

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