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LMK04033 register programming

Sa De
Prodigy 135 points
Other Parts Discussed in Thread: LMK04033, SN74LVCZ161284A, CODELOADER

Hi,


I want to use LMK04033 to generate a clock in GHz range. In order to do so I am using LPT port. I want to find out if there is any other cable to be attached to the LPT port(DB 25) or can I connect the pins (CLKuWire, DATAuWire, LEuWire) of the LMK directly to the pins on LPT?

  • 0
    TI__Mastermind 24205 points

    Hi Sa De,

    the LMK04033 EVM comes with an LPT to Microwire cable. There is a microwire header on the EVM to which this cable can be dorectly plugged into.

    Regards

    Arvind Sridhar

  • 0 in reply to Arvind Sridhar
    Prodigy 135 points

    Thanks for the reply. I am using LMK04033 on a breakout board. I have connected the pins on the breakout board according to the typical interconnection of the LMK040xx in a clocking application as shown in page 43 of the datasheet - http://www.ti.com/lit/ds/symlink/lmk04033.pdf

    I have connected the pins LEuWire, CLKuWire, DATAuWire to the pins 3,9 and 9 of the LPT port. When I send the registers by pressing either the load button in the registers tab or Loading the register one by one in the burst mode there is no change in the LPT port output which I tried to observe on oscilloscope.

    LEuWire
    CLKuWire
    DATAuWire
  • 0 in reply to Sa De
    TI__Expert 5325 points

    Hello Sa De,

    please consider that the parallel port uses 5V levels while the LMK04033 operates at 3.3V.

    Please consider following documents:

    http://www.ti.com/lit/ds/symlink/lmk04033.pdf   p.17

    http://www.ti.com/lit/pdf/snau045

    http://www.ti.com/product/sn74lvcz161284a

    Best regards,

    Patrick

  • 0 in reply to Patrick Kammermayer
    Prodigy 135 points

    Thanks for the documents. Can I connect the LPT port pins to the LMK pins after connecting the LPT port pins to resistors?


    We can also use a level shifter to convert the 5V from LPT to 3V3 of LMK.

  • 0 in reply to Sa De
    TI__Genius 10320 points

    Hi Sa De,

    Yes, this is ok. The onboard resistor dividers are configured to drop 5V levels to a tolerable 3.3V signaling level.

    What revision of board do you have?

    Gabe

  • 0 in reply to Gabe Ayala
    Prodigy 135 points

    I do not have a revision board. I am using lmk04033 on a breakout board. What would be the step-by-step procedure to load registers from code loader in this scenario.

    Using a lpt port from an usb-lpt adapter and connecting the microwire pins to lpt pins 3, 4, 9.(with resistors in between)

    I am using the load button for each register in the Registers tab but there is no response on the lpt pins output. In the burstmode tab also tried the loading 1 register setting LE low and clicking run - no output change.

  • 0 in reply to Sa De
    TI__Genius 10320 points

    Hi Sa De,

    It sounds like Codeloader isn't communicating to your LPT port. Are you simply using a generic USB to LPT adapter? Driver issues have led us to use a USB based approach to interface with our EVMs now.

    Gabe

  • 0 in reply to Gabe Ayala
    Prodigy 135 points

    Hi Gabe,

    I am using MCS7715 -- USB 1.1 to Single Serial and Single Parallel Controller -  http://www.asix.com.tw/products.php?op=pItemdetail&PItemID=115;74;109&PLine=74

    Installed the compatible driver for Windows 7. When I select the correct LPT port and go to LPT/USB -> Check LPT. It says Successfully opened LPT driver.

  • 0 in reply to Sa De
    TI__Genius 10320 points

    Hi Sa De,

    I'll close this thread as we are handling offline.

    Gabe