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TM4C123GH6PM: Table 11-6 in Datasheet is in error

Ed Carryer
Prodigy 40 points

Part Number: TM4C123GH6PM

Hi!,

It seems that Table 11-6 (on page 711) in the TM4C123GH6PM datasheet (DS-TM4C123GH6PM-15842.2741   SPMS376E) is incorrect in the Max Time Column. The times listed for pre-scale values of 0, 1 and 0xffff are correct, but the values other than those are incorrect. This can be seen as the values are increasing by a factor 2 at each step, while they should be increasing at increments of 53.687s .

How does this correction get propagated to the datasheet?

Thanks,

ed

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  • 0
    TI__Guru**** 191886 points
    Hi Ed,
    Thanks for finding the mistake. For prescaler=0x0002 the max time should be 2^32 * 37.5ns which is 161.06s, not 214.748s and likewise for the rest should be incrementing by 53.687s.
  • 0 in reply to Charles Tsai
    Guru 117855 points

    Greetings Charles,

    It was expected (by me) that the, "Change in System Clock speed" (may) have accounted for this issue.
    Yet "161/214" is not explained by the 80/120 System Clock upgrade.      And I (only) now note that poster's device is (limited) to 80MHz.    (as it is 123 class) 

    Might you (briefly) describe the origin of,  "37.5nS."        Thank you.

    On a broader note - might this same "issue" have "propagated thru to (other) devices - as well?      (Cut & Paste has such broad appeal...)

  • 0 in reply to cb1_mobile
    TI__Guru**** 191886 points

    Hi cb1,

     Ed was referring to the below table. For prescaler=0x0002 which is equal to 3*Tc with Tc=12.5ns the prescaled clock is 12.5*3=37.5. I hope I didn't mess up the math. :-)

  • 0 in reply to Charles Tsai
    Guru 117855 points

    Thank you Charles - much appreciated.

    Just as you composed your (very neat) response - I amended my writing - finally recognizing that a "123 device" is confined to 80MHz (max.)

    Your chart enables the observation that, "Tech Writer/Chartist" (likely) "seized upon" the "DOUBLING" of "Max Time" (between Tc 1 & 2) which was (unfortunately) true - but may have served to "camouflage" the fact that further chart entries would be "Additive!"      AND - this may have been avoided by the, "stricter definition" of  the chart's column two!    

    I propose - "# of Timer Clock (Tc) Multipliers" - which eliminates such ambiguity!

    Knowing the (likely) cause of such mistake - is often the best means to PREVENT their repetition ... is that not true?

    Note too that "Cut & Paste" indeed LIVES - might this issue have "visited" other devices - as well?      Again - thank you, Charles.