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I2C PMOD device --> TCP/IP (Ethernet) using Linux

Former Member

I would like to read data from an i2c device through the PMOD (such as Digilent temp sens) and write to e/net.  I've read the standard Linux OS distributed for the Zedboard has the TCP/IP functionality built in, so I think it's best to just try and use that OS but I need to add the i2c interface. I have a couple questions:

1) How might I add the i2c interface so it is accessible from Linux?
2) How do I actually read info from that device (do i2c devices have addresses for registers typically, and how to access them from Linux?)
3) How does the tcp/ip comms work on Linux?  for instance, I think the standard IP address is 192.168.1.10 for the zedboard, but how to establish a connection with it from my PC to send and receive data?

Thanks!

  • 0

    Hi there,

    I will answer your questions per bullet:

    1) You will need to use the AXI interface across the AXI-GPIO bus.  There are examples of this in the Hardware Speedway as well as in many of the reference designs.  Some manufacturers already have full up designs that you can download and use for reference.  Which I2C PMOD are you using?

    2) This depends on the I2C device, which has the registers and addresses listed in the device's datasheet.  This will end up showing up as a memory access in Linux, passing the data through the AXI interface.

    3) The linux OS already contains everything that Linux has.  You should be able to establish connectivity properly.  Can you ping the device?  If not, can you connect through the terminal and validate the IP address?  (use ifconfig for this)

  • 0

    I know the zedboard has SPI1 and I2C1 directly routed to the CPU and SPI1 pins are located to the PMODA. Don't know for the I2C1 pins tho..

    you can also invoke a Xilinx I2c ip (low freq IP catalog)
    which will plug onto the AXi bus and you can access it in baremetal or linux rather fastly (no axi understanding needed)


    you can finally code your personnal IP which you plug onto the axi bus on a specific axi protocol.

    Ethernet is routed to the CPU, don't know much about the ethernet in the Linux kernel but you might access it easily if your linux distribution supports ethernet.