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Looking for an ADC — Parallax Forums

Looking for an ADC

NewzedNewzed Posts: 2,503
edited 2007-09-24 01:30 in General Discussion
I was looking for a small ADC and came up with the MCP3004 - 10-bit, 4 channel, SPI interface.· Anyone have a better suggestion.\?· Would like to stay with the SPI interface because I understand the shiftin/shiftout stuff.

Sid



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Yesterday is history, tomorrow is a mystery, and today is a gift.

That is why they call it the present.

Don't have VGA?
Newzed@aol.com
·

Comments

  • MarkSMarkS Posts: 342
    edited 2007-09-22 00:19
    How about this one: http://www.parallax.com/dl/docs/prod/compshop/max1270.pdf
  • NewzedNewzed Posts: 2,503
    edited 2007-09-22 00:25
    Nice chip, Mark, but I don't have that much room.· Besides, its for the Propeller and I would prefer one that operates from 3 VDC.· Thanks anyway.

    Sid

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Yesterday is history, tomorrow is a mystery, and today is a gift.

    That is why they call it the present.

    Don't have VGA?
    Newzed@aol.com
    ·
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2007-09-22 02:16
    The dual version of the MCP3004 is what I've been looking at for the MoBoProp motherboard. It seems like a good match to the Propeller and should be able to sustain about 90K samples/sec at 3.3V (interpolated from specs).

    -Phil
  • NewzedNewzed Posts: 2,503
    edited 2007-09-22 12:01
    Phil, do you have an example of the shiftin and shiftout statements?· With the TLC2543 I write:

    LOW cs
    SHIFTOUT dout, clk, msbfirst, [noparse][[/noparse]ADch<<8\12]
    SHIFTIN din, clk, msbpre, [noparse][[/noparse]result\12]
    HIGH cs

    What would I write for the MCP3004?

    Thanks

    Sid

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Yesterday is history, tomorrow is a mystery, and today is a gift.

    That is why they call it the present.

    Don't have VGA?
    Newzed@aol.com
    ·
  • NewzedNewzed Posts: 2,503
    edited 2007-09-22 13:44
    Phil, I had a small design problem with the MCP3004.· I'd love to run it with 3.3VDC, but since most sensors, particularly the LM34, need 5VDC, I had to run the 3004 at 5VDC.· I added a 4.7K SMD 0805 in series with the Dout pin to the Prop so that should solve matters.

    Sid

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Yesterday is history, tomorrow is a mystery, and today is a gift.

    That is why they call it the present.

    Don't have VGA?
    Newzed@aol.com
    ·
  • Tracy AllenTracy Allen Posts: 6,666
    edited 2007-09-22 18:21
    I just used an ADS1000 in SOT23-6 package for a project where the ADC had to be right next to the measurement point. It is single channel differential, 12 bit, with a built in PGA, but it is I2C, not SPI. The ADS1100 is a pin compatible 16 bit converter.

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    Tracy Allen
    www.emesystems.com
  • NewzedNewzed Posts: 2,503
    edited 2007-09-23 14:36
    Phil, I'm making a board for an MCP3004 module on SuperMill so I can test it out before I incorporate it into a board.· The board will plug into either the Stamp or the Propeller and runs off 5VDC.· Would you like a board?· They are no trouble to make.· No charge, of course.

    Sid

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Yesterday is history, tomorrow is a mystery, and today is a gift.

    That is why they call it the present.

    Don't have VGA?
    Newzed@aol.com
    ·
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2007-09-24 01:30
    Sid,

    Sure! I'd like to see one of your milled boards. I'll email my postal address pronto.

    Thanks!
    Phil
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