Re: Parallel programming of Tiny26 on an STK500

Aha!  You got me for a second...  My supply is only ~10v, yet, when I put on a 19v
supply it didn't change anything.   I looked a little further and even with a 10v supply
(8v to the regulator) I still get a nice, clean, 12v pulse on the RESET line.   It turns
out the STK500 uses a voltage doubler off of the supply voltage to drive a zener diode
to get their programming voltage.  So, the input to the STK500 could be as low as 7v and
it will still function correctly.  That is defensive designing!

I still cannot "recover" my tiny26...

Cheers!

----- Original Message -----
From: "Jason Kyle" <[email protected]>


> At 20:53 17/05/2003 -0700, Larry Barello wrote:
> >Has anyone successfully programmed (or at least erased) a tiny26 using the
> >STK in high
> >voltage programming mode?
> >
> >I built the special cables needed, but it refuses to work.  I am kind of
> >thinking maybe
> >it simply doesn't work...  Serial programming works great until I enable
> >PB7 - whereupon
> >the only way to get the chip back is by a full erase and it ain't working!
>
> Obvious but worth checking, do you actually have +12V at the RESETn pin
> when programming?  You would need around 15V to the STK board since it has
> a rectifier and 317 regulator.  Datasheet says 11.5-12.5V is required.
>