how do I tell CCS to set the pic to use an external clock?

Nick · Guest

My pic is using the internal clock and I want it to use the external. How do I go about doing that?

Nick

rnielsen · Joined: 23 Sep 2003 Posts: 852 Location: Utah

Well, it would be nice to know ..which.. PIC you are trying to use. We only have a few different ones to pick from.

Nick · Guest

ya, that was pretty dumb of me.

pic16f767

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

If you mean the processor clock it is in the #fuses:

rnielsen · Joined: 23 Sep 2003 Posts: 852 Location: Utah

If you want to see what fuses are available just select View on the menu bar within the compiler and then select Valid Fuses. Select the correct PIC and it will show them.

I believe the correct fuse statement would be:

#fuses EC_IO, // and any others that would be appropriate

This (EC_IO) makes OSC1 your clock input and also makes pin RA6 an I/O. Don't use this if you are going to use a crystal, only if you have an external clock source.

Ronald

Nick · Guest

I found out my old version doesnt have that fuse I have 3.1, darn it.

Nick

bdavis · Posted: Wed Sep 01, 2004 9:32 pm

If you have EC, you could use that also, and the OSC2 should be OSC1 divide by 4 output, but you don't get the IO pin usage on OSC2 that you would get with EC_IO. Does it show EC as a valid OSC fuse?

Nick · Guest

no it doesnt show any of those fuse just the standard f76 ones. I'm going to get the update.

Nick

rnielsen · Joined: 23 Sep 2003 Posts: 852 Location: Utah

Just curious... is it possible to program the Configuration word with a command, something like #rom?

Ronald