ZHCSGT3C August 2017 – January 2023 DS90UB954-Q1
PRODUCTION DATA
AEQ Min/Max settings: The AEQ circuit can be programmed with minimum and maximum settings used during the EQ adaption. Using the full AEQ range will provide the most flexible solution, however if the channel conditions are known an improved deserializer lock time can be achieved by narrowing the search window for allowable EQ gain settings. For example in a system use case with a longer cable and multiple interconnects creating higher channel attenuation, the AEQ would not adapt to the minimum EQ gain settings. Likewise in a system use case with short cable and low channel attenuation AEQ would not generally adapt to the highest EQ gain settings. The AEQ range is determined by the AEQ_MIN_MAX register 0xD5 (see GUID-91F5BD60-3256-43FE-9BB9-092E6E267480.html#GUID-91F5BD60-3256-43FE-9BB9-092E6E267480) where AEQ_MAX sets the maximum value of EQ gain. The ADAPTIVE_EQ_FLOOR_VALUE determines the starting value for EQ gain adaption. To enable the minimum AEQ limit, SET_AEQ_FLOOR bit in the AEQ_CTL2 register 0xD2[2] must also be set. An AEQ range (AEQ_MAX - AEQ_FLOOR) to allow a variation around the nominal setting of –2/+4 or ±3 around the nominal AEQ value specific to Rx port channel characteristics provides a good trade off in lock time and adaptability. The setting for the AEQ after adaption can be readback from the AEQ_STATUS register 0xD3 (see GUID-8180F976-5911-49C5-8773-D6DF5F5F3875.html#GUID-8180F976-5911-49C5-8773-D6DF5F5F3875).