How to Use Internal and External Effectively

[Allen]

Hi,
I started to do a coding for Microcontroller, I have some following doubts,

1) Every Microcontroller has Clock(Which will vary controller by controller). Take it for example,
I am using a Controller which is having 32MhZ. This frequency can be changed for 16MhZ also. But how can i change this.
Is there any Hardware register to achieve this.
2) If my process is multi threading, is it possible to set a different frequency for two running thread.

3) Running RTC
i) I have seen that, RTC will run only on External Crystal. Why it will not run internal(Controller Clock)?
ii) I read some where, if want to take a reference of External Clock, Need to access from a GPIO. Is this Correct,
If Yes, how can i reference through GPIO. If No, then what should i do in program to access External Crystal.

 

 

[GANEEV SINGH]

Hi Allen

1)You can change the operating frequency using various softwares like SinaProg and all; what they really do is, they make some changes inside microcontroller's fuse bits.

2) Yes according to me you can run a multi-threaded system with different frequencies.

3) RTCs do not have their own clock; they either depend on external crystals or they acquire the clock from a microcontroller operating it.

[Author]

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