hello all,

I think I'll build this PIC-Key, that I believe some of you may know:
http://home.comcast.net/%7Ebotronics/pickey.html

Now therearea few technical question I have to ask:

1) I want to use the PIC-Key with PIC12F675 - means 8 pins. but the example in the page is for one with 40 pins!
it uses only 5 of them: 5V, MCRL, GND, B.6, B.7.
I have no idea where to connect these two last connections, to B6 and B7.
I also don't know how (should I connect it directly to the pins? should I use resistors caps etc?)

2) In this circuit (http://home.comcast.net/%7Ebotronics/pickeylay.gif) that explains the connections between the PIC-Key and the MicroPic itself, there's one diode (D1) and one Crystal with no values. How do I choose the right Diode and Crystal to this circuit?

lot of thanks.

 

When I program pics, I have VPP, VDD, GND, DATA and CLOCK (CLK). I use the ICD which has a programmer that used these signals.

If that what you are asking? Look at the 877 datasheets and see which is data and which is clock, then match them to the 675. Assuming this is an ICSP, and not something that does serial programming via a bootloader.

EDIT: Datasheet will tell you the crystal and caps you need. I would think any small signal diode 1N4148 would work. Also, depending on the PIC you can use the internal oscillator?

Disclaimer, I am not up on the JDK (or whatever unit they mentioned on the page). Just tring to help.

 

The 877 doesn't have an internal oscillator, the crystal can be any value up to 20MHz - usual values are either 20MHz or 4MHz. As you say, a 1N4148 will be fine, as will pretty well any silicon diode.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Well, I don't sure where to find the information about the oscillator. I did search.
if, any of you can tell me what should I look after, I'll be happy, AND I would be able to start the building of the circuit by tomorrow!

http://ww1.microchip.com/downloads/e...Doc/41190c.pdf

really. thanks.

 

You should connect B.7 to GP0 and B.6 to GP1.

The 12F675 has an internal oscillator that can be used. It's detailed on page 52 of the data sheet.

As a starting point for a project I would suggest using the template supplied by microchip. You will find this in
C:\Program Files\Microchip\MPASM Suite\Template\Code\f675temp.asm
This file is setup to use the internal oscillator.

HTH

Mike.
Edit, You don't mention a power supply. This circuit needs a separate 5V regulated supply to work.

 

Great.
Thanks for the note, and for the rest. I hope it will go well.