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Do you need an internal or external oscillator?
Typical oscillators can vary wildly. Specialty temperature compensating oscillators can be needed in low or high temp applications, or if temperature varies wildly. Speed. Internal oscillators may not reach the highest speed of the IC. External ones can be needed for that.
Can a 1% oscillator be used for real time clock?
A 1% oscillator would be off by over 14 minutes per day if used as the basis for a real time clock. Accurate long term time may also be needed without having to know real time. For example, suppose you want a bunch of low power devices to wake up once every hour to exchange data for a few seconds and then go back to sleep.
When do you need to share an oscillator?
Some applications want to share an oscillator. Special applications where the internal clock may not be easily used. Dividing the internal clock might be harder than throwing a cheap 31 kHz watch crystal at it, for time keeping applications.
Can A R-C oscillator be off by 36 seconds?
A 1% R-C oscillator could be off by 36 seconds though. That would add significant on-time and therefore power requirements to the devices that only needed to communicate for a couple of seconds every hour. Precision. Internal clocks are not precise, can be affected by noise.
Can a microcontroller tolerate a bad oscillator?
In my experience, many applications can tolerate the shortcomings of an internal oscillator, especially when the frequency has been calibrated at the factory. With older microcontrollers, the internal oscillator might have tolerance as bad as ±20%.
Is the high frequency oscillator factory calibrated?
The high-frequency oscillator is factory-calibrated, so a fair degree of accuracy is available. It is these internal oscillators, and their associated frequency division and selection circuits, which make the internal oscillator block, seen in Figure 12.5. Figure 12.6. Clock source block diagram
What are the advantages of a SC cut oscillator?
The main advantage of the SC cut is that it provides overall better frequency stability . This is because an SC cut has a lack of transient response for dynamic temperature changes which is due to the lack of stress sensitivity.