Is it possible to build clock generator only with cpld?

[catrat]

generate clock cpld

Hi,All
Is it possible to build the clock generator only with crystal,cpld and some capacitors and resistors?

Thanks!

 

[ze_dib]

cpld as clock generator

Hi,

What do you mean by making a clock generator ?

If you want, from a source clock, making a frequency generator configurable, you can, you just need an extern oscillator and a CPLD big enough to let you implement your two counters by clock generator and a few latchs to store divider factors.

If you want to clock you cpld with only a crystal and few capacitor, make sure it has a clok circuitry inside. If not, you have to build your own external resonator to clock your system.

Hope it helps

Ze_DIB

 

[catrat]

clock generation signal for cpld

Yes I want to clock the cpld (like altera max3000, lattice 4k series) with only crystal and some passive components, is it possible?
I wonder if I can build the oscillator with cpld internal inverter and external crystal...

 

[massive]

clock generation cpld

With CoolRunner2 an external crystal oscillator can be used without additional oscillator cirquit(inverters, etc). With other cplds you should design external oscillator cirquit and then to pass the clock signal into the cpld..

 

[dll_embed]

cpld crystal oscillator

To use a discrete component to generate clock maybe cheaper, but you may find it cause more trouble. Clock is the heartbeat of a digital system.
Whenever possible i prefer to external oscillator.

 

[bobcat1]

clock generator cpld

I have once long time ago implimented an oscillator on a PLD 16V8

at the time it was only an experiment and it work well the only problem was with the delay within the PLD device

I'm not shoure it's a good soulation.
You can use a simple "one gate chip" to impliment an oscillator or use an all ready made low cost chip oscilator

There for I cant advice you to use this methode ,an inverter inside
a cpld to form an oscillator because it depand on the cpld resource and might interduce some un wonted delays and diform the wave shep and duty cycles of the oscilator

best


bobi

 

[Mentor2003]

clock generation lattice cpld crystal

As I know - yes