SPRZ171T December   2004  – September 2020 SM320F2801-EP , SM320F2808-EP , TMS320F2801 , TMS320F2801-Q1 , TMS320F28015 , TMS320F28016 , TMS320F28016-Q1 , TMS320F2802 , TMS320F2802-Q1 , TMS320F2806 , TMS320F2806-Q1 , TMS320F2808 , TMS320F2808-Q1 , TMS320F2809 , TMS320F2809-Q1

 

  1. 1Introduction
  2. 2Device and Development Tool Support Nomenclature
  3. 3Device Markings
  4. 4Silicon Change Overview
  5. 5Usage Notes and Known Design Exceptions to Functional Specifications
    1. 5.1 Usage Notes
      1. 5.1.1 PIE: Spurious Nested Interrupt After Back-to-Back PIEACK Write and Manual CPU Interrupt Mask Clear Usage Note
    2. 5.2 Known Design Exceptions to Functional Specifications
      1.      Advisory
      2.      Advisory
      3.      Advisory
      4.      Advisory
      5.      Advisory
      6.      Advisory
      7.      Advisory
      8.      Advisory
      9.      Advisory
      10.      Advisory
      11.      Advisory
      12.      Advisory
      13.      Advisory
      14.      Advisory
      15.      Advisory
      16.      Advisory
      17.      Advisory
      18.      Advisory
      19.      Advisory
      20.      Advisory
      21.      Advisory
      22.      Advisory
  6. 6Documentation Support
  7. 7Trademarks
  8. 8Revision History

Advisory

GPIO: GPIO Qualification

Revision(s) Affected

0, A on F2809 silicon

0, A on C2801 and C2802 silicon

0, A, B, C on F2801, F2802, F2806, F2808, F28015, and F28016 silicon

Details

If a GPIO pin is configured for "n" SYSCLKOUT cycle qualification period
(where 1 ≤ n ≤ 510) with "m" qualification samples (m = 3 or 6), it is possible that an input pulse of [n * m – (n – 1)] width may get qualified (instead of n * m). This depends upon the alignment of the asynchronous GPIO input signal with respect to the phase of the internal prescaled clock, and hence, is not deterministic. The probability of this kind of wrong qualification occurring is "1/n".

Worst-case example:

If n = 510, m = 6, a GPIO input width of (n * m) = 3060 SYSCLKOUT cycles is required to pass qualification. However, because of the issue described in this advisory, the minimum GPIO input width which may get qualified is [n * m – (n – 1)] = 3060 – 509 = 2551 SYSCLKOUT cycles.

Workaround(s)

None. Ensure a sufficient margin is in the design for input qualification.