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Looking for an ADC @ 3.3V w/ I2C — Parallax Forums

Looking for an ADC @ 3.3V w/ I2C

MightorMightor Posts: 338
edited 2008-11-10 09:52 in General Discussion
Hey people,

I am looking for an ADC with I2C interface that is happy to run at 3.3V so I don't need a 2nd power supply. I'd like it be in a DIP package, as I am not quite confident enough with soldering to deal with SMDs and have no facilities or budget to have boards made. Does anyone have any suggestions? Ideally it would have 8 ADC channels, so I minimise the number of components. I intend to use it with this: http://www.pololu.com/catalog/product/960 (it can run @5V and @3.3V).

Thanks in advance!

Regards,
Xander

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Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-11-03 20:46
    This thread is not Propeller related and is being moved to the Sandbox Forum.

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    Chris Savage
    Parallax Engineering
  • John AbshierJohn Abshier Posts: 1,116
    edited 2008-11-03 22:36
    I didn't find any I2C at Digikey and all the ones I found at Mouser were surface mount. Here is an 8 channel, 8 bit in dip format. Not reading the data sheet but looking at the nomenclature, it may be easy to modify the 0834 code posted for several Parallax projects.

    John Abshier
  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2008-11-03 23:49
    Microchip MCP3208 is an 8-channel 12-bit ADC that runs from 2.7V to 5V and is available in 16-pin DIP.
    http://au.farnell.com/1084269/semiconductors-integrated-circuits/product.us0?sku=microchip-mcp3208-ci-p

    Trouble is that it's not I2C but SPI you may well say. Well true, but you connect the clock line to SCL and the DIN and DOUT together to SDA and so then all you need is a chip select. The chip is happy, the Propeller is happy, the I2C EEPROM is happy. Don't forget to add a pullup to the chip select so that it doesn't interfere with anything during reset.

    Otherwise there is the venerable PCF8591 I2C ADC but if you can spare one line use the much superior MCP3208.

    *Peter*
  • MightorMightor Posts: 338
    edited 2008-11-04 08:31
    Thanks for helping me find a solution. I will see if I can get some samples of the MCP3208 from Microchip and have a go at doing the SPI/I2C trick. Would be pretty cool if I got it working that way!
    The PCF8591 would require two chips, as it only has 4 channels on each IC. I suppose that could be an option as well if I don't get the MCP3208 working.

    Regards,
    Xander

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    | To know recursion, you must first know recursion.
    | Current projects and ramblings: I'd Rather Be Building Robots
  • JavalinJavalin Posts: 892
    edited 2008-11-04 11:14
    try this one

    http://obex.parallax.com/objects/307/

    James
  • MightorMightor Posts: 338
    edited 2008-11-04 12:05
    Javalin said...
    try this one

    http://obex.parallax.com/objects/307/

    James
    Unfortunately it seems that this IC is not available in a PDIP or CDIP package [noparse]:([/noparse] I currently have no way of using a TSSOP-16 package.

    Thanks for your time though [noparse]:)[/noparse]

    Xander

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    | To know recursion, you must first know recursion.
    | Current projects and ramblings: I'd Rather Be Building Robots
  • RomanGRomanG Posts: 2
    edited 2008-11-06 04:18
    Mightor,

    I have layout and schematics of small PCB for MCP3208 that will convert SOIC16 to DIL16 with 4.096V reference "on board" if you are interested

    Roman
  • MightorMightor Posts: 338
    edited 2008-11-06 07:05
    RomanG said...
    Mightor,

    I have layout and schematics of small PCB for MCP3208 that will convert SOIC16 to DIL16 with 4.096V reference "on board" if you are interested

    Roman
    Roman,

    I appreciate the offer but unfortunately I don't have the equipment or the budget to make the converter PCBs [noparse]:([/noparse] Thanks, though!

    Regards,
    Xander

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    | To know recursion, you must first know recursion.
    | Current projects and ramblings: I'd Rather Be Building Robots
  • RomanGRomanG Posts: 2
    edited 2008-11-06 23:25
    Xander,

    It's very easy to make, you would not need any special equipment, just laser printer and etching solution.


    Roman
    SOIC14.jpg
    101 x 95 - 4K
  • JavalinJavalin Posts: 892
    edited 2008-11-07 08:35
    or just buy one from Sparkfun....

    http://www.sparkfun.com/commerce/product_info.php?products_id=495

    Something like?

    J
  • MightorMightor Posts: 338
    edited 2008-11-07 08:44
    I really appreciate your suggestions guys, but if I order one more thing like etching fluid (plus the basins to etch in) or a board of some kind, my wife will kill me. I just spent more than 300 euro on robot-related stuff for my birthday (less than a week ago) [noparse]:)[/noparse] Ordering stuff like those nice Sparkfun adapters from the EU makes them quite expensive. So I have no budget worth speaking of, I'm afraid [noparse]:)[/noparse] I could get away with ordering a couple of components here and there, but it really ends there (or divorce, hehe). That is the reason I was looking for a ready-to-use solution.

    Xander

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    | To know recursion, you must first know recursion.
    | Current projects and ramblings: I'd Rather Be Building Robots
  • JavalinJavalin Posts: 892
    edited 2008-11-07 08:56
    or get similar from farnell in the UK

    http://uk.farnell.com/roth-elektronik/re932-04/adaptor-smd-so-16-1-27mm/dp/1426172?_requestid=73639

    J
  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2008-11-09 22:33
    Xander,

    Why are we talking about an smd to dip converter for the MCP3208 when it is already available in DIP?
    au.farnell.com/1084269/semiconductors-integrated-circuits/product.us0?sku=microchip-mcp3208-ci-p

    BTW, there is nothing special about the software just because it shares the I2C pin. If you run into problems I'm sure I could whip up a driver that will do the trick. I have my own code for MCP3208s that do the scanning and filtering etc and I frequently reuse the I2C pins in projects. The SCL line even serves as a status indicator line as I usually connect an LED to this line and flash a steady status signal whenever I am not accessing any serial device. The "blips" on this line indicate that something is at least working and of course straight after reset the Propeller accesses the EEPROM during booting which provides another visual indication that it's doing the right thing.

    *Peter*
  • MightorMightor Posts: 338
    edited 2008-11-10 09:52
    Hey Peter,
    Peter Jakacki said...
    Why are we talking about an smd to dip converter for the MCP3208 when it is already available in DIP?
    Well, I didn't, hehe. I did say that I was not comfortable with SMD soldering [noparse]:)[/noparse]

    I will order some samples of that IC and take it from there! I appreciate your offer to help and if I run into issues, I'll be sure to take you up on it [noparse]:)[/noparse]

    Thanks for all your advice everyone, but I'll go with the MCP3208 for now and see how that goes for me.

    Regards,
    Xander

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    | To know recursion, you must first know recursion.
    | Current projects and ramblings: I'd Rather Be Building Robots
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