Matrix user forums

Hi

I want to run the 18F66K80 at full speed (64Mhz), preferably using an external Xtal (but could use the INTOSC if need be), but I also want a CLKOUT at preferably 5Mhz (but could possibly push all the way up to 16Mhz) to run a few external components in sync.

Is this possible? I'm a little confused as the CLKOUT pin is on A6, bit the OCS1 & OSC2 pins are A6 & A7.

Also, how do I scale the CLKOUT frequency to 5Mhz (or 16Mhz if I really have to)?

I think I need to use the EC3IO, but not sure on how to implement it.

Thanks

Using clock out on RA6 is fine if you only want Fosc/4.
If you want a much wider choice, you can set REFOCON to give a much wider range (from fosc to fosc/32,768) on pin RC3.
See page 64 of the datasheet.

Hi Martin

Thanks for this.

The project has some what progressed since writing the last post, I have now moved on to using the 33EP64MC206 for the addtional speed an IO. For this part the datasheet says it has a REFCLK0 that is remapable and easily set within the RECOCON register.

I have never re-mapped a pin using C before (only done it using the flowcode marco's). Any chance you could help with showing me an exampe of how I would re-map the REFCLK0 to one of the RP* pins?

Thanks

Hello,

First find the RP number of the pin you wish to output the signal to. Note any pin marked RPIxx is only available as a remappable input.

Then look for the pin in the RPORx register section of the datasheet starting from page 197.

For example using RP20 the code woud look like this.
0x31 corresponds to the REFCLKO output.