Use an internal clock source ???

[Altera_Forum]

Hi again, 

 I find it amusing that i've moved all my descrete chips into an Altera (Max7000) device, and yet i still need to clock it externally on the master clock pin, sourced from a lazy 555 or a 4040 cmos counter etc etc....ultimately i'd like a single Altera device on my PCB with no extra chips required.  I wondered if there's a sneaky way to simply create a hex-invertor oscillator within the Altera device itself, with an external Xtal or R/C timing ????? anyone? anyone?  Someone mentioned to me that i shouldn't try to attempt that with the main clock input pin, but *maybe* any of the 'spare' i/o pins could possibly do this for me? Maybe the output of the hex-oscillator would then feed into the master clock pin?  My application is NOT frequency or time critical...it's simply driving a bunch of large counters for eprom addressing or flashing lights (disco) etc.... So, accuracy isn't really that much of a great concern for me....  no, i'm not trying to pll-phaselock anything down to the 14th decimal place ;-)  Thanx in advance, Marty.

[Altera_Forum]

Not recommended as there is no guarantee of the speed of the part and the RC time constant charge time might not make it high enough to sustain oscillations. 

 Get a cheap osc. and call it a night. Break open an old watch if you have to. 27 Khz I think?

[Altera_Forum]

I was afraid of that answer hehehehe. 

ok, ext-oscillator it will be then ;-)  Thanx, Marty.

[Altera_Forum]

I recently needed a source for a clock and also wished there were a simple oscillator on board to run a crystal or resonator. 

 What I found was a Crystal Oscillator Driver from TI, 1GX04, that is very small and inexpensive from their series of single-gate functions.  Regards, rfournier