Reccomended ADC chips

CumQuaTCumQuaT Posts: 156
edited November 2010 in Propeller 1 Vote Up0Vote Down
Hi all,

Does anyone have a favourite with regards to a reliable, good resolution and easy to interface ADC with the Propeller? Such a buffet of choices, but before I just start grabbing some, I thought I'd put it to the crowd to see if there are favourites among you.

Looking through the OBEX there are many, many objects for them, so it's obvious that people have their favourites to use.

I'm going to be interfacing to a set of two LPY5150AL dual-axis gyroscopes and am looking to get a nice smooth feed from them.

If you mention a favourite, any code/circuit pointers would be much appreciated also, as from my looking around I've noticed many varying opinions regarding filtering circuits and noise removal, etc.
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  • 7 Comments sorted by Date Added Votes
  • kwinnkwinn Posts: 5,981
    edited November 2010 Vote Up0Vote Down
    For general purpose use I have standardized on the MCP3208. I selected it for several reasons.
    - 12 bit resolution and 50 - 100K sample rate is adequate for most applications
    - low power requirement and operates from a wide voltage range ( 2.7 - 5.5V )
    - low cost, wide availability, and available in thru hole or smt packages
    - OBEX has objects available for interfacing to prop
    In science there is no authority. There is only experiment.
  • ThricThric Posts: 109
    edited November 2010 Vote Up0Vote Down
    I agree with using the MCP3208. I'm currently using two IXZ500 gyros connected to the ADC and it works really well.

    If you do use the MCP3208 i'd recommend the attached program and don't forget to attach 3.3v to the Vref pin.

    I'm not using any kind of filtering right now even though I should, but so far I haven't seen a problem yet.
  • CumQuaTCumQuaT Posts: 156
    edited November 2010 Vote Up0Vote Down
    Sounds good, gents! Thanks for the pointers! I'll see if I can source a few from my supplier.
  • caskazcaskaz Posts: 763
    edited November 2010 Vote Up0Vote Down
    Hi.

    I also had getting TouchScreen's value to use MCP3204(4ch) in PropForth.
    This is very useful and easy to connect on Propeller.
  • Peter JakackiPeter Jakacki Posts: 4,524
    edited November 2010 Vote Up0Vote Down
    I have used the MCP3208 and they are very easy to use but of course they take up 3 or 4 I/O lines and still require an external voltage reference unless you are happy with just using the supply voltage.

    Some years ago I was searching for 12-bit ADCs in a small package with on-board reference etc that didn't cost an arm and a leg. I had noticed that there were many low cost CPUs that fitted this requirement so I started using them as Programmable Peripheral Controllers (PPCs).

    Of course they need software but this was minor and so I am able to connect the PPC using the same I2C lines as the EEPROM and then Flash the PPC from the Prop initially after which it is just another peripheral. An ADC based upon a PPC can do so much more than any ADC can such as filtering, buffering and threshold detection etc as well as simplify (faster) the I2C access methods. It is very unlikely that I would ever use another dedicated 8 to 12-bit ADC again in any of my designs.

    Here is one such chip, it's only $2.80 for one-off. There are other types in DIP and other packages.
    http://au.mouser.com/ProductDetail/Silicon-Labs/C8051F986-GM/?qs=sGAEpiMZZMvu0Nwh4cA1wYpXCxJDYb0i4AiRuBCa1Ow%3d
  • HannoHanno Posts: 1,130
    edited November 2010 Vote Up0Vote Down
    3208 is great for slow speed. Take a look at ADC08100 for high speed- up to 80Msps with the Propeller- great for decoding NTSC video.
    Hanno
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