reading  a serial digital sensor should there be a

reading a serial digital sensor should there be a resistor on its output? the output seems to get random noise random 1s where zeros should be whale its printing the sensors input that should be fixed.ads1298 dout page 13

“Specifications apply from 0°C to +70°C. Load on DOUT = 20pF || 100k[ch937].”

It all depends on what sensor we are talking about. Unfortunately my crystal ball is on the blink so you will have to tell me its part number and even supply a link to the data sheet.

here is the link to the data sheet http://focus.ti.com/lit/ds/symlink/ads1298.pdf

The inputs are now all grounded.
The first word that is 24 bits that comes out is the status.
This shows what pins are unconnected & the GPIO pins status.
1100 is alwase there it is supposed to be...
0000 0000 is the 8 inputs if they were connected but this part of the chip is turned off so they should stay 0s.
the last four bits are GPIO I set them as inputs I can make them 1s orr 0s.
But if I have my loop part of my program read 9 24 bit words and print only the first one.
Ocationaly the 1st word gets a number it is not configured to output.
The print command could be taking too long and things are getting messed up that way.

Your English is not very proper. It hurts to read your post. Why don't you check your spelling here before posting?

You need to show us some code and actual data you received.
There's something I don't quite get:

the last four bits are GPIO I set them as inputs I can make them 1s orr 0s.

If you have 4 GPIO, and you set them as INPUTS, then you CAN'T MAKE them 1 or 0. You CAN if you set them as OUTPUTS. If all that surprised you were these four bits (is that what you meant?), you shouldn't. Inputs are free to float if you don't tie them down.

A word is defined in most systems as two bytes, which is 8 bits. So a word is 16 bits.

I might have got what was wrong I set the ADC to 250 samples per second. At 500 S.P.S. the time it takes to print could have caused problems with the timing of everything else.

The GPIO pins of the ADC I set as inputs so I could put a wire from them to 0v GND or 3.3v Power. then read the results on the screen. That way I could debug the interface between the arduino and the sensor.

Thank you both for your help I will try to post better in the future and find a avitar image others are not using. I have not seen many people use this one.

Richard, I was thinking about the same thing. I changed it. Now I am a happy smurf jumping up and down.

josheeg, if you read your GPIO without anything connected to them you will read random values, unless you connect some pull-up or pull-down resistors.