Progrmming PIC16F84A

[Nigel Goodwin]

That the 16F84A need external ossicalator like RC...??? What about 16F628??

yes i believe they are the same in that respect

But the 628 has the HUGE advantage that it has an internal 4MHz RC oscillator, which allows it to have up to 16 free I/O pins on an 18 pin chip (whereas the 84 only has 13). It also makes layout far easier, no messing about with crystals and capacitors - and the internal 4MHz oscillator is accurate enoguh for most purposes.

I might also mention the 16F819, basically a 628 but with internal 10 bit A2D, and an 8MHz (but selectable for other speeds) internal oscillator.

 

[amady]

That the 16F84A need external ossicalator like RC...??? What about 16F628??

yes i believe they are the same in that respect

But the 628 has the HUGE advantage that it has an internal 4MHz RC oscillator, which allows it to have up to 16 free I/O pins on an 18 pin chip (whereas the 84 only has 13). It also makes layout far easier, no messing about with crystals and capacitors - and the internal 4MHz oscillator is accurate enoguh for most purposes.

I might also mention the 16F819, basically a 628 but with internal 10 bit A2D, and an 8MHz (but selectable for other speeds) internal oscillator.

So how i want to design the external oscillator using R and C. I think i don't want to use cristal in order to reduce my costing... what the suitable value for R and C??? Before this i'm try to use R=330K and C=220pF... this is following from the website:

**broken link removed**

 

[Nigel Goodwin]

So how i want to design the external oscillator using R and C. I think i don't want to use cristal in order to reduce my costing... what the suitable value for R and C??? Before this i'm try to use R=330K and C=220pF...

The datasheet gives the formula for calculating them, but you could try those values and see what it runs at.

 

[amady]

The datasheet gives the formula for calculating them, but you could try those values and see what it runs at.

Datasheet... ? Where can i get the datasheet?? :roll:

 

[williB]

https://www.electro-tech-online.com/custompdfs/2004/10/35007b-1.pdf

page 24..