SPRZ457H January   2021  – December 2023 AM2431 , AM2432 , AM2434 , AM6411 , AM6412 , AM6421 , AM6422 , AM6441 , AM6442

 

  1.   1
  2. 1Usage Notes and Advisories Matrices
    1. 1.1 Devices Supported
  3. 2Silicon Usage Notes and Advisories
    1. 2.1 Silicon Usage Notes
      1.      i2287
      2.      i2351
    2. 2.2 Silicon Advisories
      1.      i2049
      2.      i2062
      3.      i2103
      4.      i2184
      5.      i2189
      6.      i2236
      7.      i2185
      8.      i2196
      9.      i2207
      10.      i2208
      11.      i2228
      12.      i2232
      13.      i2244
      14.      i2245
      15.      i2091
      16.      i2235
      17.      i2303
      18.      i2317
      19.      i2134
      20.      i2257
      21.      i2277
      22.      i2285
      23.      i2310
      24.      i2311
      25.      i2313
      26.      i2328
      27.      i2241
      28.      i2279
      29.      i2307
      30.      i2320
      31.      i2329
      32.      i2331
      33.      i2243
      34.      i2249
      35.      i2256
      36.      i2274
      37.      i2278
      38.      i2306
      39.      i2363
      40.      i2312
      41.      i2371
      42.      i2366
      43.      i2138
      44.      i2253
      45.      i2259
      46.      i2283
      47.      i2305
      48.      i2326
      49.      i2368
      50.      i2383
      51.      i2401
      52.      i2409
  4.   Trademarks
  5.   Revision History

i2243

PCIe: Timing requirement for disabling output refclk during L1.2 substate is not met

Details

PCIe base specification requires Refclk to reach idle electrical state within 100ns of CLKREQ# deassertion when entering L1.2 substate (please refer TL1O_REFCLK_OFF parameter).

This timing requirement cannot be met when sourcing Refclk from the device since hardware does not automatically gate Refclk. Refclk gating has to be performed by software by writing to PHY_EN_REFCLK field in SERDES_RST register.

As a result, Refclk cannot be gated in L1.2 substate. Generally, allowing Refclk to run in L1.2 substate is not expected to cause any functional issues. However, if gating Refclk within 100ns is required by the system, L1.2 substate cannot be supported.

Workaround

Use an external Refclk generator to supply the PCIe reference clock