OSCCAL bit calibration

[Vovachess]

Hello.

How correctly to calibrate oscillator to 4Mhz of PIC10F204? There is calibration word saved at 0xFF. What to do with it? How does software must look like?
Thanks

[Ttelmah]

You do nothing.
When the chip wakes up, it actually resets to the top location in memory. This instruction executes, and transfers the factory calibrated value, into the W register. It then 'rolls over', and starts executing at address 0. The compiler automatically transfers this byte, into the OSCCAL register for you. The only thing you need to do, is, whenever you program the chip, you must make sure your programmer is set to save this byte.
If you look at the listing file the compiler generates, you will see, something like:

[Vovachess]

Thanks
I cheched hex file.
It works.