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AD9154 Data Key NCO Alignment

Question asked by on Jul 14, 2018

Step 1: refer to AD9154 datasheet's DEVICE SETUP GUIDE, JESD204B link is okay.

Step 2: refer steps to achieve a data key NCO alignment are as follows:

1. Set NCOCLRMODE (Register 0x050, Bits[1:0]) = 0b10.

2. Write the expected 16-bit data key for the I and Q datapath into NCOKEYIx (Register 0x051 to Register 0x052) and NCOKEYQ (Register 0x053 to Register 0x054), respectively.

3. Set NCOCLRARM (Register 0x050, Bit 7) = 1.

4. Send the expected 16-bit I and Q data keys to the device to achieve NCO alignment.

5. Check the alignment status:

 NCOCLRMTCH (Register 0x050, Bit 5) = 1. But NCOCLRPASS (Register 0x050, Bit 4) = 0 and  NCO_ALIGN_FAIL (Register 0x050, Bit 3) = 0.

This result of 0x050  is different with datasheet info ( If NCO phase alignment was successful, NCOCLRPASS (Register 0x050, Bit 4) = 1. If phase alignment failed, NCO_ALIGN_FAIL (Register 0x050, Bit 3) = 1.)


So please help to check the reason of this NCOCLRPASS (Register 0x050, Bit 4) = 0 and  NCO_ALIGN_FAIL (Register 0x050, Bit 3) = 0, how to get correct value of 0x050 as datasheet?