Synchronized clock frequency

[Guest]

Hi,

I have to read an ADC that work at 4Mhz max.
My problem is that my PIC (18F452) is working at 40 mhz and it must be synchronous with ADC.
how can i get a frequency of 4Mhz synchronized and derived from the main clock?
I thought to use SETUP_POWER_PWM, but I dont understand it.
Can anoyone help me ?

Thank you

[PCM programmer]

The 18F452 doesn't have a Power PWM module. It only has a normal
PWM module.

Here is a thread which discusses using the PWM output as a clock source:
http://www.ccsinfo.com/forum/viewtopic.php?t=27712

If you take the code shown in that thread, and use an 8 MHz crystal
in 4x PLL mode (so it runs at 32 MHz), then you can get a 4 MHz clock
signal from the CCP1 pin. I tested this and it works.

You can't do it when running at 40 MHz (with a 10 MHz crystal) because
the Timer2 is clocked at Fosc/4, which is 10 MHz. To get a 4 MHz PWM
output, you would need to divide by 2.5, and you can't do that.
That's why you must run it at 32 MHz (with an 8 MHz crystal).

Example: