thanks tom

Finally i noticed that on the circuit diagram their is a conn1 and conn2, would this be for programing the chip? is their a component that would be placed there?

Thanks
Jack

 

CONN1: The USB input.
CONN2: The PICkit 2 programmer or similar programmer input.

You can place whatever component easily allows you to connect the devices here. Are you building this on a breadboard, stripboard or PCB?

Small signal usually means just an indicator LED. Like the one you might find on consumer equipment. You can pretty much substitute any red, green or yellow LED (you cannot substitute blue, white, IR or UV LEDs.)

The schematic explains where everything connects to. The LED matrix is a complex beast, it is 'charlieplexed' to allow six LEDs to be controlled with only three pins. Let me know if you need any help with this part of your program.

 

I was looking around and found this
http://www.mcuhobby.com/articles.php?article_id=7&rowstart=0
it's a build your own pickit. I thought it would be good fun to put together and widen my knowledge a bit!

I am slightly nervous about the programing aswell with the "charlieplexed" method but looks good!

Jack

 

The problem with that kit is that you need to pre-program the microcontroller, and that requires a programmer.

Unfortunately to start the clone you have to program the firmware into the 18F2550 - you will need a secondary programmer for this. Once the PICKit2 firmware has been programmed into the 18F2550, you can upgrade it without the need of another programmer, because the firmware also includes a bootloader.

The PICkit 2 also has a built in variable power supply so you can interface with 3.3V devices or any supply of your choosing.

 

thanks for spotting that!
At school we use a usb to 3.5mm jack cable that has got an inbuilt chip in the cable. We also use a program called PIC Logicator to program the chips.
I was wondering if I would be able to do that as I already have a cable?
Thanks

 

I have added some pics to show u what i mean!

http://www.genieonline.com/ - The website that explains it a bit better.

 

Yes, I've dealt with those, but they are for PICAXE chips, which are already programmed with a bootloader; the bootloader then makes it easier to program via a simpler cable like the one you've got. You can try PICAXE chips for the program though, because it doesn't require anything special. You'll have to find a 12F675 PICAXE, I don't even know if they sell them.

 

Tom,
Why is your schematic an "impossible to see" negative with blue and green lines on a black background instead of a normal "black lines on a white background"??

 

I kind of got used to it; it makes it easier to use for me (more contrast; though I can still use the light version well.) gschem has Dark and Light schemes. But here's a light version for you if you prefer that.

 

Your new pastel lines on a grey background are not the usual black lines on a white background.

 

I'm sorry; I don't know what you want me to do. There's a EPS (encapsulated PostScript) output for printing which is black on white. I like gschem's output and it's perfectly readable for me. Here's the EPS version. I had to rename it as PDF because the forum doesn't support EPS files it seems, but it should work, you might need to rename it.

 

First you posted a schematic with dark lines on a black background.
Then you posted a schematic with pastel lines on a grey background.
They are difficult to see.

Most clear schematics have black lines on a white background like your schematic that I modified.

I never heard of your software and never heard of an EPS file type.

 

The software I use is not widely used because it only runs on Linux. There are no Windows versions as of yet. I like Linux and gschem, it suits me well. I like the colour schemes and honestly I don't care to modify them, because I can read them.

If I want, I can edit the Scheme/Lisp theme definitions to suit me better, but I am fine with them.

http://en.wikipedia.org/wiki/Encapsulated_PostScript

... can be opened by most good PDF readers, including Acrobat (I believe) and Evince. It was standardised by Adobe.

I use GPL EDA. I don't use Eagle, although I have tried it out on Linux, and I have to say CadSoft have done a good job porting it to Linux, it's not some crappy Windows version built on Wine, but I have no intention of using as of yet, because I like gEDA.

 

hi,

can u tell purpose of 5 led. i will give circuit.

 

Purpose of the six (6) LEDs is to show status in whatever way the OP feels necessary. In my case I gave an example of one status LED and five bargraph LEDs indicating state of charge, but the program can be written to show anything.