Anyone here familiar with digital potentiometers?



  • I am trying to learn how to use this damn thing I bought lol.

    The data sheet I have http://www.mouser.com/ds/2/268/22060a-53835.pdf

    the one I got http://www.amazon.com/Microchip-Digital-Potentiometer-10K/dp/B007R9UTMQ?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00

    How do I use this on a breadboard lol I'm new to circuitry.



  • @chris-mccaslin The device you reference uses the SPI interface. While I am familiar with SPI in general, I am not familiar with how it is used on the Omega. In particular which Omega pins are used to control SPI.
    In general, other than the obvious power connections, the general connections used with the SPI interface are:

    • MOSI - master out slave in data - called SDI on your device
    • MISO - master in slave out data - called SDO on your device
    • SCK - clock, supplied by master - same name on your device
    • CS - chip select - used by master to select/deselect the device - optional if only one SPI device is used in which case it can be hardwired to the select state (low on your device)

    Thus, you will need to find a suitable SPI library for the Omega (I believe there are some) and ascertain what pins it uses (or how they can be specified).
    Then, you will need to write any required code that uses the SPI library to send the specific commands that your device needs as described in the data sheet you referenced.

    In general, whenever there is an option to use SPI or I2C versions of devices, I prefer I2C. While in general it is slower than SPI, it uses fewer pins (only 2 however many I2C devices you have), is easier to use and well supported on the Omega.

    If you can find an I2C digital potentiometer in a suitable form factor, I would recommend that over the SPI one.

    Good luck :-)



  • @Kit-Bishop Thanks for the help with what you told me and page 31 and page 1 on the data sheet plus this it shouldn't be to hard to figure this out.

    https://wiki.onion.io/Tutorials/Using-SPI



  • Your MCP4131 are bit careful for use with SPI.

    3.3 Serial Data In / Serial Data Out (SDI/SDO)
    On the MCP41X1 devices, pin-out limitations do not allow for individual SDI and SDO pins. On these devices, the SDI and SDO pins are multiplexed.
    The MCP41X1 serial interface knows when the pin needs to change from being an input (SDI) to being an output (SDO). The Host Controller’s SDO pin must be properly protected from a drive conflict.

    Please check datasheet page 41. You can see the "Typical MCP41X1 SPI Interface Connections (Host Controller Hardware SPI) " wireing.


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