On Sunday 11 September 2005 04:30 am, Chen Xiao Fan scribbled:
> I think I heard those thing among people using JDMs.
> JDMs are cheap though. Wisp628 is slightly more expensive
> but will still take one day to build. JDM or similar
> can be used to bootstrap the Wisp628. Wisp628 is much more
> reliable. I do not want to get into wars of programmer
> though. So please ignore this if you still prefer to
> use JDMs. I have played with PonyProg in year 2002 to
> program some EEPROMs and found out it could also program
> AVRs and PICs. However I since found it not as good as
> those intelligent programmers with MCU inside.

No, I don't prefer to use the JDM -- it was a quick hack-together for testing.  
I prefer to purchase a decent supported programmer, but did not want to spend 
$160 on it (for the original ICD2).  And when I find one that works properly, 
I intend to pick up a second one, as I always like to have a backup device.  
I had thought of getting Olin's easyprog ($59 each if I build it myself), but 
it did not list the 16F818/819 as supported devices, and I prefer Linux.  I 
tried the ICD2 clone because it was very low cost, and I am planning to 
experiment with LPLAB under Linux to use it.

I did find Rob's webpage with the updated Linux Wisp software, but Wouter's 
page still does not list the F818/F819 as supported devices.  It's not that 
new, but there must be a reason that these programmers have avoided these 
devices. ???


> My guess is that Vpp are not really controlled in
> most JDM units and it will "soft-destroy" the internal IC
> but the chip will recover after sometime. But this
> is only a guess. If this is correct, I will guess
> Neil's ICD2 clone does not properly regulate Vpp.
> The original ICD2 is using a boost converter with
> a digital poti to control the output voltage (Vpp)
> and the digital poti is not cheap. So most of the
> cheaper clones will try to avoid it. Most of
> the cheaper clones will probably avoid the boost
> converter as well.

Correct -- this ICD2 uses an offset 78L12 to generate the Vpp.


> ...
> ICd2 should be able to control the sequence of
> Vdd and Vpp. That is why I think it is rather a software
> bug. Still I could be wrong.
> ...

To clarify then, your original ICD2 does have the ability to control Vdd, 
right?


Cheers,
-Neil.


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