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* z w$ C# c+ g( ^不確定是不是這個問題造成的,但可以參考一下這些資料。
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+ {) k. T7 D% r! [3 A- O$ n6 F. h) }下面這段話是肥死卡好(Freescale)的技術文檔節錄下來的,講得一針見血、但內容較雜( 不只討論這個問題),我給你另一篇 ATMEL 的技術文檔,它專門討論 MCU 的 Start-up Time,淺顯易懂、還有一些電路上的建議!& l' M1 g4 k9 R: |
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Long Start-Up Time# W* K7 [& h+ ~& P
A long start-up time is usually a more common problem with low-frequency crystals, since they tend to start much more slowly than high-frequency crystals. One of the causes of a long start-up time is weak loop gain. Oscillator start-up times will also be affected by the rise time of the power supply. When the power supply has a sharp rise time, the crystal will experience an energy impulse that will usually make it start faster than it would using a power supply with a slow rise time.
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