Values on segment are unstable.

[Sid2286]

Hi,
I'm trying to display the adc values on seven segments. I'm using mcp3208 and the file mcp3208.c.
The units place digit is flickering however the input to mcp is rock steady. I googled and made necessary changes such as decoupling cap at i/p etc. But nothing has helped so far.
Please suggest something.

[gpsmikey]

Without seeing the circuit and software, it is tough to really nail it down, but there are a number of factors. What does your Vref signal look like on the chip - if that is not perfectly stable, you will get wandering results. You may also want to consider adding a software filter to the results since you want to be able to view the results and are not going for a high data rate sample speed. There was recently another post here where Ttelmah showed how to implement a simple rolling average filter that did not use a lot of ram for array storage. See this post for details
http://www.ccsinfo.com/forum/viewtopic.php?t=44115
There will almost always be some variation down at the lower couple of bits - various noise sources in the system, the actual value may be right on a bit boundary etc.

mikey
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mikey
-- you can't have too many gadgets or too much disk space !
old engineering saying: 1+1 = 3 for sufficiently large values of 1 or small values of 3