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oscillator frequency for pov display

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Disha Karnataki

Disha Karnataki

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i want to make a pov display. i am going to use 8051uc for that so i have p89v51rd2 chip but now i have to put an oscillator for it the oscillator usually used is 11.0592Mhz frequency oscillator.
SO MY QUESTION IS CAN I USE A HIGHER FREQUENCY FOR THE SAME MICRO-CONTROLLER CHIP OR HAVE I TO USE ""EXACTLY"" 11.0592MHZ ONLY..??
 

hello

check on the datascheet of p89v51rd2, what is the maximum frequency for FOSC
Maybe because this value of 11.0592 -> 0x1B00 is a round binary value for baud rate definition
Google has many answers
https://answers.yahoo.com/question/index?qid=20081031121702AAKUzo5

The reason we use 11.0592 MHz crystal is it generates baud rate that is compatible with PC's baud rates i.e. it can generate exact baud rates of 300, 1200, 4800, 9600, 19200 bps whereas if we use other crystal values then those exact baud rate cannot be generated. This doesn’t mean that we cannot use other crystals for serial communication the error generated is very small & hence can be used if data to be send is not very large.
Click to expand...
 

i followed that link it was mentioned something like this & i dinot get that point please explain:::

""The crystal frequency for 19.2K baud is:
11.0592 = 19200 x (256 - 0FDH) x 384 / 2
(smod is 1 for 19.2K baud)


Other values can also give good results, but 11.0592 is one of
the higher speed crystals that allows high baud rates"".
what to they mean that

Other values can also give good results, but 11.0592 is one of
the higher speed crystals that allows high baud rates"".
means if at all i use a crystal with 15mhz then i will not get higher baud rates???
 

The relation between crystal frequencies and achievable baud rates is caused by the limitations of the baud rate generator. The problem isn't to get a high baud rate but to match the standard baud rates supported by other equipment e.g. a PC with the available divider factors.

What you should do:
- Decide about the baud rates required by your application.
- Find the highest crystal frequency that can generate it.
 
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