Lpc2000

Leon:

Do you find any instability with your JTAG debugger?  I'm very confused as 
to why this would be instable, and if it is, why hasn't anyone figured out 
why and fixed it?  Considering the cheapest alternatives are several 
hundred dollars more expensive, I'm confused why we don't have a rock solid 
wiggler compatible JTAG debugger developed.

-- Sean

At 02:31 PM 1/16/2006, you wrote:
>----- Original Message -----
>From: "Ed Schlunder" <zilym@...>
>To: <lpc2000@yahoogroups.com>
>Sent: Monday, January 16, 2006 7:09 PM
>Subject: [lpc2000] Building DIY wiggler w/74VHC08
>
>
> > I'm thinking of building the DIY wiggler so that I can program and
> > debug some LPC2103 chips on the cheap.
> >
> > I see the wiggler.txt schematic in the files area. It is using a
> > 74AC244 chip to do voltage level conversion between the PC and the
> > LPC21xx chip. It only seems to use 4 line drivers of the 74AC244 chip
> > (half the chip is left unused).
> >
> > Would there be any problem with using a 74VHC08 quad 2 input AND gate
> > chip instead? I would just tie one side of each AND gate high so that
> > it can be used as 4 line drivers. This chip is cheaper and smaller
> > than the 74AC244.
> >
> > The schematic also uses a DTC114 NPN transistor. I don't have any
> > DTC114 transistors. Would MMBT3904 work okay instead?
> >
> > Any other tips for a DIY wiggler?
>
>My version in jtag.zip definitely works!
>
>What you propose should be OK. Don't forget to link pins 8 and 15 on the
>DB25 connector if you are using the Macraigor software.
>
>Leon