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发表于 2013-4-25 11:55:52
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本帖最后由 a9191389 于 2013-4-25 11:59 编辑
Altera 不用说了:
http://www.altera.com/literature/an/an496.pdf
Lattice 直接有内部振荡器
On-Chip Oscillator and Timer
An internal oscillator is provided for use in miscellaneous housekeeping functions such as watchdog heartbeats,
digital de-glitch circuits and control state machines. The oscillator is disabled by default to save power. Figure 13
shows the block diagram of the oscillator and timer block
The out-put OSCOUT is the direct oscillator output with a typical frequency of 5MHz, whereas, the output TIMEROUT is the
oscillator output divided by an attribute TIMER_DIV. |
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