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Author Topic: Watchdog oscillator frequency  (Read 420 times)
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Grand Blanc, MI, USA
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Was just reviewing the watchdog timer in the datasheet for the ATmega328P, and while it's nominally advertised as having a 128KHz clock, from the chart below it seems that the design point is around 10% slower than that. Might this represent some sort of safety factor to allow slightly "late" watchdog resets to squeak through?

* wdt_osc.png (34.16 KB, 781x439 - viewed 14 times.)

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The accuracy of the 8MHz RC oscillator is rated as +/-10%.  If the same applies to the Watchdog oscillator, then it might be that the design frequency is chosen so that the real frequency never (or rarely) exceeds 128kHz.

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