ADF7242 No RF signal

Good morning everyone!

I designed a PCB according to the offical schematic(SCHEMATIC);

Now , the register in ADF7242 can be read and written and the state of ADF7242 is ok from the SPI.

When it  was running with working codes(load data and RC_TX ), it can't detected RF signal.

 

 

Thanks for your help!

  • 0
    •  Analog Employees 
    on Oct 16, 2017 1:59 PM

    Can you please just clarify a few things so that I may be better able to help.
    Have you followed the initialization procedure on Page 36 of the datasheet?

    Is your RF problem TX only or does it affect RX also?

    Is it just modulated data affected or are you able to generate a TX CW signal?

  • Thanks for your help!

    1. I did the initialization procedure on Page 36 of the datasheet.

    2. The code is working when use the EVAL-ADF7242-PMDZ, but not my PCB 

    3.  I found that when gave the RC_RX command after the RC_PHY_RDY, the status will go wrong as 0xff.

  • 0
    •  Analog Employees 
    on Oct 21, 2017 3:31 PM

    Thanks for the updated information. What I am still unclear about is if the issue is related only to the RC_RX command or other SPI commands also and you are using RC_RX command as an example. Reading 0xFF from the status register does seem strange. Does this register provide legitimate results in the PHY_RDY state or if you enter the RC_TX command? Do you have access to the SPI lines to check them on a scope to verify that they are as you expect?

  • Thanks, Dave-B!

    1. SPI can get legitimate result after giving the PHY_RDY command.( 0x83) 

    2. If the RC_TX command be given , the status  also is 0x83.

    3. When the RC_RX command be given ,the status is 0xFF. but in  EVAL-ADF7242-PMDZ is 0xA4 

     

    Thanks you!

  • 0
    •  Analog Employees 
    on Oct 24, 2017 11:34 PM

    Thanks for your answers. It is possible that you are reading the status word before it has settled. Can you please leave either a 1ms delay before reading the status or issue a NOP command after the RC_RX command and then read the status.