SPRZ397K November   2012  – September 2024 TDA2EG-17 , TDA2HF , TDA2HG , TDA2HV , TDA2LF , TDA2SA , TDA2SG , TDA2SX

 

  1.   1
  2. 1Introduction
    1.     Related Documentation
    2.     Trademarks
    3.     Modules Impacted
  3. 2Silicon Advisories
    1.     Revisions SR 2.0, 1.1, 1.0 - Advisories List
    2.     i202
    3.     i378
    4.     i631
    5.     i694
    6.     i698
    7.     i699
    8.     i727
    9.     i729
    10.     i734
    11.     i767
    12.     i782
    13.     i783
    14.     i802
    15.     i803
    16.     i807
    17.     i808
    18.     i809
    19.     i810
    20.     i813
    21.     i814
    22.     i815
    23.     i818
    24.     i819
    25.     i820
    26.     i824
    27.     i826
    28.     i829
    29.     i834
    30.     i837
    31.     i840
    32.     i841
    33.     i842
    34.     i843
    35.     i847
    36.     i849
    37.     i852
    38.     i854
    39.     i855
    40.     i856
    41.     i859
    42.     i861
    43.     i862
    44.     i863
    45.     i868
    46.     i869
    47.     i870
    48.     i871
    49.     i872
    50.     i874
    51.     i875
    52.     i878
    53.     i879
    54.     i880
    55.     i882
    56.     i883
    57.     i884
    58.     i887
    59.     i889
    60.     i890
    61.     i893
    62.     i895
    63.     i896
    64.     i897
    65.     i898
    66.     i899
    67.     i900
    68.     i901
    69.     i903
    70.     i916
    71.     i927
    72.     i929
    73.     i930
    74.     i932
    75.     i933
    76.     i936
    77.     i940
    78.     i2446
  4. 3Silicon Limitations
    1.     Revisions SR 2.0, 1.1, 1.0 - Limitations List
    2.     i596
    3.     i641
    4.     i833
    5.     i838
    6.     i844
    7.     i845
    8.     i848
    9.     i850
    10.     i851
    11.     i853
    12.     i857
    13.     i858
    14.     i876
    15.     i877
    16.     i892
    17.     i909
  5. 4Silicon Cautions
    1.     Revisions SR 2.0, 1.1, 1.0 - Cautions List
    2.     i781
    3. 4.1 106
    4.     i827
    5.     i832
    6.     i836
    7.     i839
    8.     i864
    9.     i885
    10.     i886
    11.     i912
    12.     i926
    13.     i931
    14.     i935
  6. 5Revision History

i845

USB2.0 False Detection of Disconnect Condition

CRITICALITY

Low

DESCRIPTION

Per the standard, the 'Envelope detector' in the USB2.0 PHY must indicate High Speed disconnection when the amplitude of the differential signal at the downstream facing driver's connector is greater than or equal to 625 mV, and it must not be indicated when the signal amplitude is less than or equal to 525 mV at our connector. The default configuration of the USB1/USB2 phy is such that the detector circuit is monitoring the during the entire SOF frame and not just the last 8b portion of the extended EOP as indicated in the standard.

Due to this constant monitoring, it is possible that the PHY may falsely indicate disconnect condition due to reflections on the PCB. These reflections could exceed the disconnect thresholds if TI PCB layout guidelines for USB are not strictly followed.

WORKAROUND

SW Workaround: During USB2.0 PHY initialization, configure: bit 31 of 0x4A08 404C (USB1) or 0x4A08 504C (USB2) to =1b. This will limit detection window to the proper time and prevent false disconnect. TI PCB layout guidelines for USB should also be strictly followed to minimize reflections to within the thresholds defined in the standard. See device Data Manual for details.

REVISIONS IMPACTED

SR 2.0, 1.1, 1.0

TDA2x: 2.0, 1.1, 1.0

DRA75x, DRA74x: 2.0, 1.1, 1.0

AM572x: 2.0, 1.1