Clock out, CLKO, buffer requirements?

Having searched the datasheets for AVRs which support clock out, I cannot seem to find an equivalent circuit diagram or similar to answer my question.

I want to output my system clock to provide a clock souce for another device, to save on another crystal and caps - however, I'm just wondering if I need to buffer the clock signal prior to feeding it into another device - which would entirely defeat the point of trying to save on board space.

Logic would say no buffer needed, as the relevant section in the datasheet that says the system clock can be output is called 'Clock Output Buffer', so I'm assuming this is a buffer internal to the AVR.

Just thought I'd check before I commit a design?

The clock output pin of an AVR chip is on a separate circuit, no need to buffer it.

You do have to set a fuse bit to enable it, you'll need an ISP programmer to do that.

On a ATmega328 it's bit 6 of "Fuse Low Byte" and the clock will appear on PB0 (digital pin 8 of an Arduino Uno).

It is somewhat frustrating that a fuse needs to be set to use it, I know... It would be nicer if there were a specific register access routine like that for using the watchdog that would enable you to use it.

It's none of the chips that come on Arduino boards I'm using, but AVR none the less. Thanks!

jtw11:
It is somewhat frustrating that a fuse needs to be set to use it, I know... It would be nicer if there were a specific register access

Most AVR developers use ISP programmers so setting fuses isn't a problem, it's all just part of the process.

The clock might be needed at bootup (before any software runs).

PS: You can get basic ISP programmers for $3 on eBay. They're a good investment as soon as you step outside the Arduino box (or even before...)

There's also Arduino-as-ISP - using an Arduino as an ICSP is supported in the
Arduino software.

This is a project which dosen't involve the Arduino library or IDE at all indeed.

The programmer is no issue, I've got an ISP MKII & Dragon which I regularly use. Thanks for all the input.