Hi Art,

Thank you for your input.
Please do not take my reply the wrong way and try to understand my points that follow.

The exercise was to keep the design to a minimum component count, explore unknown features of the PIC processors (unknown to me at the time), be able to modulate a high frequency carrier with the same PIC 10F or 12F family and finally have the most flexibility over the output frequency and duty cycle output. You can not bit the accuracy of the internal clock of the newer PICs if you are trying to use any RC timing circuits and employing any kind of external crystal oscillator defeats the purpose of the exercise.

As Henrik pointed it to me I love having the opportunity to use “the hammer” when it comes to replacing older ways of doing things. I grew up with doing things the hard way and I am convinced now that employing different caliber PICs the job is much easier.
Just to give you a stupid example: try designing an oscillator with a flexible frequency and duty cycle in a wide range using discrete components and you will find yourself in a deep trouble especially when one of the parameters changes.

Use the results of this thread exercise and you will find that all it takes to change one parameter is one or two lines of code. You can use the same hardware over and over for one or multiple projects and all it takes is code changes.

I’m old. My eyes are failing me and even though I can still replace a 100 pin SMD chip with 0.5 mm pitch (that means remove the old chip and install the new one) in less than 3 minutes with 100% success (my personal record about 15 years ago was 87 seconds) I do want to keep using this skill to a minimum.

So to answer your question:

The external clock divided by 4 gives only 50 / 50 duty cycle and only one output frequency for any given main clock. Second part of your question goes in the territory that I’m trying to escape from and gives very little flexibility when changing any parameter because it has to be done in the hardware.

I’m not being lazy I’m just trying to be more efficient when it comes to using my time especially when the clock is ticking for me on the down side.

Thanks for your suggestions and keep up the good work. I’ve been following your posts in this forum and I commend you for your great contributions.

Regards,

Nick