Can you please check my circuit?

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I am trying to make a PPPD programmer work, but just can't manage... I have built the SP12 cable, with some modifications that should not have any effect. But the programmer reads 0xFF no matter what. So basicly it does not work :((
I have built half a dozen design, none of them works. The LPT port works, I'm sure of that, i have checked it out with some LEDs... But I have noticed something strange... The Input pins on the LPT are high when it is disconnected... is that normal?

I am using an Intel 2,4Ghz, 512 RAM ( i don't think that makes a difference, but it doesn't hurt now, does it?), Windows XP with giveio.sys installed, ATMEGA8515-16PU, and an LPT extension cable male-to-male, NOT interconnect.

I'm using the SP12's soft, provided on the same web page as the circuit, http://www.xs4all.nl/~sbolt/e-spider_prog.html

And Here is my design:

Attachment(s): 

axos88

Last Edited: Wed. Jan 24, 2007 - 03:23 PM
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One thing I see is that, your resistor (R1) is connected between RESET and VCC, as it should be but, the capacitor (C1) is also connected between RESET and VCC.

Is this correct for this programmer design?

Usually, the capacitor (C1) is connected between RESET and GND while, the resistor (R1) connects between RESET and VCC.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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well take a look yourself, but as i see it, that's the way it should be connected:

axos88

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The second drawing that you show apears to be the correct configuration for RESET while, your first drawing apears to be incorrect.

So, which way do you have RESET wired?

Do you have C1 connected between RESET and VCC - possibly the incorrect way.

Or, do you have C1 connected between RESET and GND - the known correct way?

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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C1 to RESET

axos88

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...and the other end of c1 is going where? It's going to VCC in your drawing. That's wrong.

Go electric!
Happy electric car owner / builder

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Yeah hehe, oops... I wanted to say C1 to GND :))

axos88

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axos88 wrote:
C1 to RESET

Ok, let me just say it simply...

Capacitor (C1) needs to be connected between RESET and GND while, resistor (R1) needs to be connected between RESET and VCC.

In your self-made schematic, you don't show capacitor (C1) as being wired correctly.

But... Capacitor (C1) is shown correctly in the second schematic that you posted.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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How long is your cable? More then say 12 inches will be a problem.

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axos88 wrote:
Yeah hehe, oops... I wanted to say C1 to GND :))

I would suggest that you verify your wiring to the correct schematic, correct any wiring errors and, update your self-made schematic.

When you are absolutely sure that your wiring and schematic are correct, re-test your hardware.

If your programmer still doesn't work, re-post the correct schematic.

Also, I would suggest that you re-check this self-made interface (I think you used the term "Extension") cable.

I've been making cables of one sort or another all of my life and, I still can't seem to get them right - even as reasently as last week.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

Last Edited: Wed. Jan 24, 2007 - 03:13 PM
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Quote:
Yeah hehe, oops... I wanted to say C1 to GND Smile)

Sorry, I have drawn it incorrectly

axos88

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And about that cable, I bought it from a shop, it's a shielded 1.8m (or 6ft) cable, male to male, pinN to pinN, so that shouldn't make a problem.
Only the circuit is made by me

EDIT: I have updated the schematics

axos88

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Ok, I'll bite.... what is C2 and R2 doing?

Go electric!
Happy electric car owner / builder

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i have no idea, but i think the guy said something about reducing "ringing"

axos88

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axos88 wrote:
i have no idea, but i think the guy said something about reducing "ringing"

That would be true with the smaller schematic that you posted. But in the last Self-made schematic that you posted, it looks to me like R2 & C2 only take up space.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston