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AD9625 : Unexpected K-Character on JESD204

Question asked by SCO on Jun 5, 2015
Latest reply on Jul 9, 2015 by IanB

Hello,

I'm using AD-FMCADC2-EBZ Eval board wich carries an AD9625 ADC which transfers data to an FPGA using JESD204B link.

 

After power up I get synchronisation K characters until I generate a SysRef pulse which triggers SYNC to go High after some periods.

 

Just after that ADC send ILAs frames (4 frames) and everything looks good. Then I get user data wich looks OK.

 

BUT, JESD IP core into my FPGA detects unexpected K-Character which induces SYNC to go low for one clock period (most of the time).

And times to time, SYNC is going low for a longer period of time which causes ADC to restarts Synchronization process.

 

By disabling SCRAMBLING into ADC I checked that unexpected K-character are received (For instance K31.7=0xFF or K30.3=0x7D).

 

Why this errors occurs ? Could it comes from faulty ADC ? Is it a known issue ?

Or does something else can cause this type of errors (wrong ADC configuration)

 

Thanks in advance for your help.

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