AVR Best time possible Pulse width change Ph. correct top = ICR1

[azadfalah]

Hello friends


what is Best time possible Pulse width change Ph. correct top = ICR1

I act as follows, is it correct?

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Code C - [expand]
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if(SetNewvalue) {
     while(TCNT1H != OCR1AH && TCNT1L != OCR1AL);    
     OCR1AH=0x0C; // set New Value
     OCR1AL=0x80;  // set New Value
}

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[KlausST]

Hi,

Read the datasheet.

It tells that OCRxx registers are double bufferd and are automatically (by hardware) updated at TOP or BOTTOM or immediately depending on seleted WGM

Klaus

 

[andre_luis]

I was not able to understand anything at all from your question as you did not spent much effort to elaborate, but by looking at it, the evaluation of the 16-bit timer at 2 different moments sounds like weird, since depending on whether the values are close to the overflow of the lowest register, after updating the higher register can give a false result.

I would do something like this:

     while(TCNT1 != OCR1A);

Instead of this:

     while(TCNT1H != OCR1AH && TCNT1L != OCR1AL);

Regardless of whether your updating logic is correct or not.