bad time

[dreamproject]

hi all,

nice to be back . haven't posted in a while . !!. How are you all ?

I am using an LM629 motioncontrol IC. It needs a 6 Mhz. sytem clock . The LM629 is being programmed by a 16F877 pic . Can i use the clock out from the pic to provide system clock to the lm629 or do i have to provide a seperate clock . If this to be done with a 6 Mhz. crytal , it has two pins but the system clock needs to be input on only one pin on the lm629. Can i use a 555 for this . I heard that the 555 is unstable at such high speeds.


Thanks in advance

 

[Nigel Goodwin]

hi all,

nice to be back . haven't posted in a while . !!. How are you all ?

I am using an LM629 motioncontrol IC. It needs a 6 Mhz. sytem clock . The LM629 is being programmed by a 16F877 pic . Can i use the clock out from the pic to provide system clock to the lm629 or do i have to provide a seperate clock . If this to be done with a 6 Mhz. crytal , it has two pins but the system clock needs to be input on only one pin on the lm629. Can i use a 555 for this . I heard that the 555 is unstable at such high speeds.


Thanks in advance

If you use a 6MHz crystal on the PIC, you can feed from the clock out pin to the LM629 - depending on the input impedance of the 629, you may need to buffer it first.

You can't really use an RC oscillator at those types of speeds, particularly a 555!.

 

[dreamproject]

buffers

Hi all,
Thanks for your help . But How Do i buffer the circuit ???

 

[Nigel Goodwin]

Re: buffers

Hi all,
Thanks for your help . But How Do i buffer the circuit ???

With a buffer amplifier, high impedance input, and low impedance output - a single transistor or FET is commonly used. But try it without first, and see if it works (if it doesn't it'll probably stop the PIC clock).