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Valued Contributor III
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Use an internal clock source ???

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.
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Valued Contributor III
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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?
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Valued Contributor III
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I was afraid of that answer hehehehe. 

ok, ext-oscillator it will be then ;-) 

 

Thanx, 

Marty.
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Valued Contributor III
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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
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