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EVAL-AD9213 Output Data Inversion

Hi,

For the EVAL-AD9213 Board I can see from the schematic that the Differential Data Output Lanes are as follows:

Lane 0: Normal

Lane 1: Normal

Lane 2: Inverted

Lane 3: Inverted

Lane 4: Normal

Lane 5: Inverted

Lane 6: Normal

Lane 7: Inverted

Lane 8: Normal

Lane 9: Normal

Lane 10: Normal

Lane 11: Normal

Lane 12: Normal

Lane 13: Normal

Lane 14: Normal

Lane 15: Normal

I am working to interface with an Intel Stratix 10 TX Transceiver Eval board and utilize only the first 8 Lanes at a relatively low speed of 3.0 GSPS.

In order to correct the Signal polarity, I would expect to do the following.

1.  Enable Data Inversion by setting register 0x622 to 0x04

2.  Write register 0x5ea to 0xac to Invert Lanes 2,3,5,7.

I am monitoring the output of the Intel JESD 204B IP via signal tap, and I have tried this and I have not seen any effect on the datastream.  

Are there any additional settings in the register map that need to be set?  Is there a specific order in the initialization of when these settings need to be set?

Thank you,

Will

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  • Umesh,

    Thank you for the quick response.  I am not using that exact Intel Eval board outlined in AN905, but this one.

    https://www.intel.com/content/www/us/en/products/details/fpga/development-kits/stratix/10-tx-signal-integrity.html

    It is very similar in its design and I am following the setup and I have a lot of the process which appears to be working.  What I am finding is that when I change the ADC into test pattern mode (custom user definite data) some of the data comes out as expected, but other patterns do not.

    In my setup, I have the JESD IP block for Intel initialize and report to be that the data is aligned and the 256 bit data coming out is valid.

    If I set the enable the test pattern register 0x505 to 0x2e, I can then send custom data by writing register 0x559.

    Here is the basic output I receive

    <Register Value 0x559> : <Output Data of JESD block (256 bits)>

    0x00 : 0x0000000000000000000000000000000000000000000000000000000000000000h

    0x01 : 0x0100000001000000010000000100000001000000010000000100000001000000h

    0x02 : 0x0200000002000000020000000200000002000000020000000200000002000000h

    0x03 : 1C000000030000001C000000030000001C0000001C0000000300000003000000h

    0x04 : 0400000004000000040000000400000004000000040000000400000004000000h

    0x05 : 1A000000050000001A000000050000001A0000001A0000000500000005000000h

    0x06 : 190000000600000019000000060000001A0000001A0000000600000006000000h

    0x07 : 0700000007000000070000000700000007000000070000000700000007000000h

    0x08 : 0800000008000000080000000800000008000000080000000800000008000000h

    0x09 : 1600000009000000160000000900000016000000160000000900000009000000h

    0x0A : 150000000A000000150000000A00000015000000150000000A0000000A000000h

    0x0B : 140000000B000000140000000B00000014000000140000000B0000000B000000h

    0x0C : 130000000C000000130000000C00000013000000130000000C0000000C000000h

    0x0D : 120000000D000000120000000D00000012000000120000000D0000000D000000h

    0x0E : 110000000E000000110000000300000011000000110000000E0000000E000000h

    0x0F : 0F0000000F0000000F0000000F0000000F0000000F0000000F0000000F000000h

    There is a definite pattern here which I am trying to understand.  I still have to do the data mapping but that is secondary to understand what is going on here.  If no bits are set or all bits are set or just a single bit, 1,2,4 in binary are set, then everything is good, else there is a pattern, but a very strange one. 

    So I wanted to see if somehow the above-mentioned data lanes are inverted and causing the output data to be incorrect.  I am trying to correct this inversion on the ADC side via the registers mentioned above.

    Is this not possible to do from the ADC side from those registers?  

    Will

  • Umesh,

    An update.  Since the upper 8 lanes of JESD have no inversion on the eval board, I mapped the upper 8 lanes to the lower 8 lanes in the ad9213 register map and modified my FPGA image to use these lanes versus the original and rebuilt.  I was able to synchronize the JESD interface and now my test data pattern mentioned above outputs the expects all 1,2,3, etc. and not the inverted data.

    I am able to proceed in my testing but if possible I would still like to understand why the per lane data inversion didn't work and what is the proper sequence to enable this functionality as it may benefit others.

    Thank you,

    Will

  • Hi Will,

    Thank you for using the AD9213, and for sharing your work.

    I apologize for the trouble and confusion. Registers 0x5EA and 0x5EB are not the correct registers for lane inversion.

    Registers 0x5F1 Bits[7:0] and 0x5F2 Bits[7:0] are the registers to use for lane inversion. These are 2 8-bit registers. Each bit controls the inversion of one lane. A logic 0 value means no inversion; logic 1 value means invert.

    Register 0x5F1 Bit[x] controls the inversion of Lane x.

    For example, Register 0x5F1 Bit[0] controls the inversion of Lane 0

    Register 0x5F2 Bit[x] controls the inversion of Lane [x+8]

    For example, Register 0xx5F2 Bit[0] controls the inversion of Lane [8]

    The new information has been submitted for the next datasheet revision.

    Once again I'm sorry about the error.

    Doug

  • Doug,

    Thank you for the update.  I'm sure this will help someone in the future.  I will try these registers with my original image to verify.  As a side note, is there any place on the ADI website to get a complete list of errata for devices like the AD9213 and the AD9208? 

    Will

  • Hi Will,

    I'm sorry but I do not know of such an errata list location.

    Doug

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