This article shows how to use an ADC chip on your next project.
Introduction
For this this project you can either choose to use the MAX186 or
the MAX187. The differences between these two chips are described
below.
The MAX187 is an 12 bit on
The code for the ADC for pbasic is incorrect here and at Shaun’s website. The code could simply be fixed by setting serDin to 3 and serDo to 2. I was getting random values for the most part till I switched those numbers, and then i was getting the correct values.
Mike,
Any luck with your noise problem? I’m using a similar design - I have two MAX192 (8 channel, 10bit version of the MAX186) and a 74HN595 (shift register latch) using the same bus. I’m using the chip select on the ADC’s and ‘latch’ on the 595’s to select the chips. No problem on the output to the chips- but my results from the ADC are mostly random. I’m suspecting noise.
I’m using a pair of 74LS259 decoders to selectively supply 5v to the sampled channel - Im measuring an automotive thermo-resistor (going through a divider).
The circuit Shaun provides above worked on a breadboard - but once I put it all on a PCB, I’m getting noise. I should probably get an o-scope to see where the noise is. Based on your comment, I wonder if my Basic Stamp 2pe is also the source of the noise. The capacitors in Shaun’s circuit are probably ‘tuned’ to eliminate noise at a particular frequency.
Shaun says he is using a BS2 (20MHz), your BS2p40 is 20MHz turbo, my BS2pe is 8MHz turbo. I suspect that changing the .1uf cap to match would help. Thoughts?
Hi,
Nice article. Im using the MAX187 in one of my projects just like you have in your article :
My resolution is very good but on the output of my Voltake follower Im picking up a 70Khz signal !!! I followed the Max187 Grounding reccomendations but I still have this noise. Im also using a BSp240. I believe this is the Internal clock from the ADC. Have you seen this beofre? Any advice would be appreciated
