gnupic: Thread: A question

Hi,

I'm new to PIC's, however, I'm an engenar. I made a programmer consists of
7407 connected to the LP0 port. I had several mistake during the hardware
building.

My question is: Can the PIC16F84 be damaged if the programming voltage is
there for 10 minutes (cont) or more?

How can I make sure that my circuit works?  I run pp in debug mode, and all
the signalls are now working correctly however I can not program the PIC.

Please suggest me something. Thanx:

Leva

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This message was generated by Sylpheed.

On Sat, Apr 26, 2003 at 03:55:10AM +0200, Leva wrote:
> Hi,
> 
> I'm new to PIC's, however, I'm an engenar. I made a programmer consists of
> 7407 connected to the LP0 port. I had several mistake during the hardware
> building.

Do you have pullups on the 7407 outputs?

> 
> My question is: Can the PIC16F84 be damaged if the programming voltage is
> there for 10 minutes (cont) or more?

No. There's no time limit that Vpp can be on MCLR so long as the voltage 
doesn't exceed 14V.

> 
> How can I make sure that my circuit works?  I run pp in debug mode, and all
> the signalls are now working correctly however I can not program the PIC.
> 
> Please suggest me something. Thanx:

Cable length. It's almost always the problem when the static signals seem to
be correct but it doesn't work.

Try a short cable (0.5 m or less). You'll probably get better results.

BAJ