PIC Questions

[wmmullaney]

Hello again, i was looking at this pic PIC16F628, is there a compatible pic that has an internal oscillator? I was looking at this programmer, is the serial connection male or female?

(R1 is 2.2k)

 

[wmmullaney]

can I use 5k resistors?

 

[Nigel Goodwin]

Hello again, i was looking at this pic PIC16F628, is there a compatible pic that has an internal oscillator?

The 16F628 has an internal oscillator, that's why I chose it for my tutorials, plus it was the replacement for the popular old 16F84.

 

[wmmullaney]

Ok, must have missed it in the data sheets, were can I find your tutorials?

5k Resistors?

 

[wmmullaney]

Found this.

**broken link removed**

Is "R" needed?

 

[Gayan Soyza]

Your programmer will give you trouble in a small variation on your comport voltages & in your supply.In your programmers it needs external 5V.If the voltage exactly 5V you don't need the resister.Most JDM type uses 5.1 zenners.

Try making the JDM programmer here is the simple version of that working well.
No need external supply.
**broken link removed**

 

[Nigel Goodwin]

Ok, must have missed it in the data sheets, were can I find your tutorials?

In my signature at the bottom of all of my posts!.

5k Resistors?

It's a crude nasty 'programmer', and they tend to give lots of problems, and only work on some computers.

 

[wmmullaney]

Ok, I'v seen the uJDM, kinda wanted something simpler just to start, after that I want to get a JDM programmer from Sparkfun.

So, 5k resistors will work.

I hope to have my projects up and running by Christmas.

 

[Nigel Goodwin]

Ok, I'v seen the uJDM, kinda wanted something simpler just to start, after that I want to get a JDM programmer from Sparkfun.

The JDM is really too simple to be reliable, and is fussy about the particular machine it's connected to.

 

[wmmullaney]

What do you suggest? I don't have 50+ dollars to spend. Or to many parts to build one with.

 

[wmmullaney]

Is the PIC16F628 compatible with the PIC16f84?

 

[matc]

Define "compatible" ? It's not the same part, but check the datasheets for pinout compatibility.

 

[Nigel Goodwin]

Is the PIC16F628 compatible with the PIC16f84?

It replaced it last century, the 84 has effectively been obselete for a LONG time now. The 628 is cheaper, higher spec, and pin compatible with the 84, requiring only extremely minor changes to the source code to run.

 

[wmmullaney]

I meant in a programmer.

 

[wmmullaney]

On the "simplest programmer in the world" what does he mean when he says vdd not to be pulled higher than .5v?

In fact, the clamp diodes to Vdd is not diodes, but transistors, and about 80% of the current flows into ground. Because of this, are Vdd not to be pulled higher than Vdd+0.5V, even all the inputs pulls high.

Does this mean R is needed? even if the 5v is regulated?

 

[wmmullaney]

If r is needed, can it be 350 ohms?

 

[blueroomelectronics]

You really need to get an assortment of resistors, if you're this limited with the hardware available why don't you simply use the free simulator that comes with MPLAB?

You could try the trivial programmer as seen on Lothar Stolz's site for programming his ICD2 design. It uses the IC-Prog software http://www.ic-prog.com/
Don't forget you'll need to add the 0.1uf caps across the power pins, a 22K resistor from MCLR to VDD (5V) and an oscillator for most of the older PICs like the 16F877A
**broken link removed**

 

[wmmullaney]

You didn't answer my question, will the programmer work without r, if not can I use 350ohm?

 

[blueroomelectronics]

Maybe, why don't you build it and find out. They YOU can tell us if it works.

 

[wmmullaney]

Well, I don't want to ruin the pc or a pic, I guess I'll just use something close to your design.