Software Trim Idea

[Suraj143]

Hi ericgibbs here normal temperature = 28C I'm using 4Mhz external XT.

 

[ericgibbs]

Hi ericgibbs here normal temperature = 28C I'm using 4Mhz external XT.

Hi,
Lucky you, its 0C here and snowing again.!

As you may know, osc can change freq with tempr.
Whats the tempr and stabilty spec on the xtal. ?

 

[Pommie]

One more question.
At start how did you get 64 remainder?From what value did you divide?
Roman Black initialize his accumulator with 100256uS on power up.

If you continually subtract 256 from 1,000,000 until the value is less than 256 you get 64. This can be done in excel as mod(number,256) or number-INT(number/256)*256. The number you start from doesn't really matter as the error will only happen on the first time period. For simplicity I started from 1,000,000.

Mike.

 

[Suraj143]

Hi Mike sorry for confusing I have missed a 0 (zero).I was adding 100,000 it should add 1000,000.

Now everything is understood.Thanks for your great help.

 

[Suraj143]

Hi,
As you may know, osc can change freq with tempr.
Whats the tempr and stabilty spec on the xtal. ?

I don't know I just asked for 4Mhz crystal they give us.No data sheets

 

[ericgibbs]

I don't know I just asked for 4Mhz crystal they give us.No data sheets

hi,
As you are using an external xtal, why not this one.

**broken link removed**

 

[blueroomelectronics]

Or 4,915,200 they also make for excellent baud clocks.

I think the clock routines are very neat though.