555 oscillator???

[hotrodhed120]

can a 555 ic be used as a reliable oscillator for a pic16f870? I'm new so take it easy in the details, please.

 

[eng1]

I don't think so. For time-sensitive applications you need a crystal. Otherwise, you may use an RC network, without any external chip.

 

[Hero999]

No, if you want acuracy and don't want to use a PIC, use a counter and oscillator IC like the CD4060.

 

[Sceadwian]

I'd trust the internal oscillator of a PIC over a 555.
If you need a reliable clock a crystal is usually your best choice.

 

[Gayan Soyza]

can a 555 ic be used as a reliable oscillator for a pic16f870? I'm new so take it easy in the details, please.

why you adding a more cct for a PIC?Just use a crystal (accurate) or a RC network For applications where precise timing is not a requirement.

 

[Nigel Goodwin]

As suggested, a 555 would be completely pointless - the PIC can use a simple resistor and capacitor as it's oscillator, and will be at least as stable as a 555. But if you need any sort of precision, then use a crystal.

 

[k7elp60]

As Nigel said it is pointless to use a 555 as an oscillator for the PIC. However it is possible to make a 555 timer extremely stable when using film capacitors
for timing, and you don't need the Vcc to be highly regulated.

 

[Hero999]

I don't see the point in using a PIC if you're just going to use an external timing RC network unless you wany long delays. A TS555 costs less than a PIC and will be as accurate as a PIC with an external RC timing network.

Please don't get what I'm saying confused, of course a using PIC using the internally trimmed on-chip RC oscillator is more accurate than a 555.

 

[Nigel Goodwin]

I don't see the point in using a PIC if you're just going to use an external timing RC network unless you wany long delays. A TS555 costs less than a PIC and will be as accurate as a PIC with an external RC timing network.

I think you're missing the point (or I am?), the question is about using a 555 to replace the crystal on a PIC - not about using a PIC to replace a 555.

 

[hotrodhed120]

Thanks for all the response guys it has helped alot.