• TI Thinks Resolved

AFE7444EVM: LED D7 LMK LOCKED doesn't light up after set mode

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Replies: 5

Views: 152

Part Number: AFE7444EVM

Hello,

I would like to configure the AFE7444EVM in mode 4 using the internal mode.

My configuration is identical to the videos as well as the User Guide. 

  • AFE74444EVM

  • DC power supply 5.5V 5A

  • sinusoidal 10MHz 1.9Vpp reference (on LMK CLK IN SMA connector)

  • mini USB cable from the kit

  • TSW14J57EVM

  • DC power supply 12V 3A

  • USB cable from the kit

The AFE7444EVM and TSW14J57EVM are connected to each other. The AFE7444EVM JP9 jumper is in position 2,3 (internal clock mode).

I have configured the TSW14J57EVM in mode 4 before the AFE74444EVM.

Thus, when applying mode 4 on the AFE7444EVM, its clock should be configured at the same time and therefore light up LED D7 (LMK LOCKED). However, this is not the case in our tests.

Also, when we select mode 4 for the AFE7444EVM, we are supposed to see, in the drop-down list, some modes grayed out meaning they are not selectable due to the DAC and ADC frequencies selected earlier. Here again, it is not, all the modes are selectable as if the software didn’t take into account our previous choices. The version of the AFE74xxGUI software that we have is 2.2.9.

Finally, when we set the TSW14J57EVM to mode 4, the TX SYNC LED doesn't light up, like in your videos, but if I turn off the AFE7444EVM, that same LED lights up as it should. The RX SYNC LED is actually on.

So here are my questions:

- Why does the D7 (LMK LOCKED) LED not light up after applying mode 4 to the AFE7444EVM?

- Is the 10MHz reference on the LMK CLK IN input really necessary for operation in internal mode?

- Why all modes are selectable despite the frequency preselection and does it have an impact on the wrong configuration of the clock?

- Why does the TX SYNC LED not light up after applying mode 4 on the TSW14J57EVM?

- Could I have the latest version of AFE74xx GUI software ?

- Could I have screenshots of your configuration in internal mode ?

- Why both inputs CLKin0 and CLKin1 are enabled when input 0 seems to be connected to nothing on the schematics ?

- Could you also provide an effective python configuration script ?

  

Thanks for your help.

Have a nice days.

William

  • Hi Willian,

    10Mhz input to LMK is optional when on-board clock generation is used. It can be used to lock on-board 122.88MHz crystal oscillator to external 10 MHz reference frequency. When "Set Mode" button is clicked, LED D7 turns on to indicate LMK PLL2 is locked. So it should light up irrespective of whether 10 MHz clock is connected or not. When 10 Mhz reference clock is connected, LED D6 should also light up  indicating that LMK PLL1 (on-board crystal) is locked to the 10MHz clock.

    Regarding the other questions, I will setup the EVM in lab and verify this and get back to you tomorrow. 

    Regards,

    Vijay

  • In reply to Vijayendra Varma Siddamsetty:

    Hi Vijay,

    First of all, thank you very much for your quick answer.

    I continued to investigate in the meantime. I think part of my problem, is that reading registers from the AFE74xxEVM does not work, while writing does.

    To be sure, I decided to re-program the STATUS_LD1 and STATUS_LD2 outputs of LMK0482 in order to light up LEDs D6 and D7 respectively.

    According to the LMK0482 datasheet, by programming (via the Low Level View tab of the AFE74xx GUI) the registers 0x15F and 0x16E to the value 0x04, I observe that the LEDs light up. Reading gives me zero everytime, regardless of the state of the LED. I observe the same behavior from the Python script below;

    GUI_Module = __ import __ ('AFE74xx')

    GUI = GUI_Module.Device_GUI ("AFE74xx")

    GUI.write_register ("LMK04828", 0x016E, 0x04)

    val_ld1 = GUI.read_register ("LMK04828", 0x015F)

    val_ld2 = GUI.read_register ("LMK04828", 0x016E)

    print ("Status LED LD1 =% d"% val_ld1)

    print ("Status LED LD2 =% d"% val_ld2)

    Reading does not work either.

    And to put it simply, we can't read the version number, or any other registers.

    Even more surprising, by plugging a logic analyzer on the SPI bus connected to the LMK

    HTSW-104-07-G-T-.240, only the LMK_CS shows signs of life, whether writing or reading.

    Do you have any idea why reading isn’t working?

    Thank you again for your help.

    Have a nice day.

    William

  • In reply to William LE CORRE1:

    Hi William,

    I have setup an AFE7444EVM and verified that when I click "Set Mode" button, LED D7 (LMK PLL2) lights up. Can you get this? (as you said SPI writes to LMK are working). I'm also able to read back chip ID (register 0x003 reads back value 0x06). 

    Also you say writing into LMK registers is working for you. But you don't see signal on LMK_SCLK and SDI when writing? 

    Regards,

    Vijay

  • In reply to Vijayendra Varma Siddamsetty:

    Hi Vijay,

    As I told you before, when I press the Set Mode button, the LMK doesn’t seem to be program.

    I can confirm that I can write and read the evaluation board, but only, by switching both AFE7444 and LMK04828 to 4-wire SPI mode, instead of 3 by default.

    print '# Set LMK : 4 wires for SPI bus '
    GUI.write_register("LMK04828", 0x000, 0x10) #3 wire mode disabled
    GUI.write_register("LMK04828", 0x14a, 0x33)

    print '# Set AFE : 4 wires for SPI bus '
    GUI.write_register("AFE76xx_GLOBAL",0x00, 0x30)

    if False:
    val_r0 = GUI.read_register("AFE76xx_GLOBAL", 0x00)
    print("\t| Reading of AFE register 0x000: 0x%x (expected 0x030)" % val_r0)

    The python script "Example startup sequence.py" , properly configure the LMK after execution (leds D7 and D6 light up, as well as led PLLREFLD).

    It therefore seems that the problem came from the AFE74xx GUI software and the python scripts used.

    Can you send me the latest version of AFE74xx GUI software (and working pythons scripts) please ?

    Have a nice day.

    William

  • In reply to William LE CORRE1:

    Hi William,

    GUI version 2.2.9 is the latest one. I have been testing with the same version. If you want to re-install to be sure, please download 'Setup_AFE74xx_EVM.exe' from AFE7444 secure folder (ti.com/mysecuresoftware).

    GUI is configured to use 4 wire mode for both LMK and AFE. So it is expected for SPI readback to work in 4 wire mode. 

    Regards,

    Vijay