Search this site and search the web for Frequency Generation, and read and learn the contents of "the bible" as it's called here. That's the set of literature that completely explains how the 805x architecture works. Once you know that, you will find this problem TRIVIAL.

You will, of course, have to resolve issues with respect to the system clock, which is the counter/timer's timebase, vs. the desired oscillator frequency, which may be critical to your serial communication if there is any, but you'll find there's no difficulty once you have learned the concepts described in "the bible."

In order to do this with utterly NO firmware overhead, will probably require a compromise in precision of your 38KHz output, or in the precision of your baud rate, if you use serial communication.

Since you haven't said anyting about serial comm's, and haven't said anything about the required precision of your output, whether it has to be 1 part in 10^15 or one part in 10^3, I'll assume you haven't even thought about that yet.

The information is all here, though, and you need merely search for it.

RE