ADS42JB49: Unable to lock LMK04828 on ADS42JB49 EVM

Yogitha,

In the box labeled as "PLL1 N Mux" (in the bottom of the GUI), change the setting to "Feedback". In the "Holdover and LOS" box, disable "Use Hitless Switching". Make sure jumper JP5 has the shunt installed between pins 1-2 and JP2 has a shunt between pins 1-2.

Regards,

Jim 

Jim,

Thanks for the quick response.

I tried the things you mentioned but it didn't help. When I change the PLL1 N MUX to feedback the LMK LOCKED led is going OFF.
The jumpers JP5 and JP2 are properly set.

Regards,
Yogitha

Any help on this issue? I couldn't figure this out yet.

Thanks,

Yogitha

Yogitha,

I just ran this evm with the GUI default configuration with no problems. Please check your settings with the ones attached. You must press the board reset after power up and before you load the configuration file. What revision is the EVM you have?

Regards,

Jim

ADS42JB49.pptx

Hi Jim,

I configured the EVM with the same settings you shared but still the LMK LOCKED led is always blinking. 

By board reset do you mean the switch SW4 (LMK RESET)? After power on I press this reset and then load config file.

However, once the EVM is configured and then I press this SW4 I don't see any any difference with the led status (D4 ON, D1 Blinking). I am using Rev D board.

Below are the configuration settings

Thanks,

Yogitha

Yogitha,

Not SW4, SW1 (ADC reset). You need reset the ADC, not the LMK. Press this after power up and before loading the configuration file.

Regards,

Jim

Hi Jim,

I pressed the SW1 - ADC reset before loading configuration and still the Led's status is same.

Thanks,
Yogitha

Hi Jim,

I checked that R19 is properly installed. There is an 100MHz oscillator present which is connected to the OSCINP pin of the LMK04828 and the D4 led is always ON after configuration. We do not have an external clock source right now, so need to reference the on board oscillator.

How can I figure out the problem with the LMK and get it working?

Thanks,

Yogitha

Hi Jim,

I generated a 100Mhz clock on SMA J10 and connected it to KC705. Through signal tap I could see a decent clock on the FPGA port. I will confirm the clock quality using the oscilloscope. I will also confirm the 10MHz clock on R19  soon.

But then if the clock is properly generated on J10 does that mean the LMK is working fine?

Thanks,

Yogitha

Hi Jim,

I have generated the clock on SMA J10 and connected it to KC705. Through signal tap I observed that a stable clock is received at FPGA port. I will confirm the quality of clock using the oscilloscope. Also on the 10Mhz clock on R19 I will confirm with the scope soon.

But then if the SMA J10 clcok is properly generated does that mean LMK is working fine and that ADC and FPGA clocks will be properly generated?

Thanks,

Yogitha

Yogitha,

I think your LMK is working fine. Does your setup look like the one in the attachment? Do you have the ribbon cable installed between the TSW14J10 and the KC705? When you open HSDC Pro GUI, are you able to load the firmware in the FPGA? If so, what is the status of the LED's on the KC705? If the firmware is not loading, send me screen shots of the HSDC Pro GUI.

Regards,

Jim

KC705.ppt 

Hi Jim,

I have checked the R19 installed on back of the board. I could see 10MHz clock on both sides of the resistor. I have followed the steps you have mentioned to generate 100MHz clock on ClockOut6. I see a ~248Mhz clock instead of 100. For whatever divider value I set for the clock, it always generates 248MHz clcok.

Below are the oscilloscope snapshots.

Clock on both sides of R19

DclockOut6 with divider set to 30

Thanks,

Yogitha

Yogitha,

In the GUI, there is a LMK04828 tab. Click on this then send me screen shots of every tab under this one. Then send the register settings for the ADC and LMK that you are using by going to the Low Level View and clicking on "Save Config".  While in the Low Level View tab, did you verify you can write and read properly to the registers in both parts?  

Regards,

Jim

config_file.cfgHi Jim,

Please find the screenshots below

I was able to verify the Register read and writes through GUI. 

Thanks,

Yogitha

Yogitha,

Everything looks fine as far as I can tell. You may just have a bad board. See the link below regarding EVM exchange/returns.

Regards,

Jim

www.ti.com/.../faq-returns-and-refunds.html