Re: [avr-chat] Dragon: mega slow at dumping Flash, normal ?

[Vincent Trouilliez]

On Sat,  4 Jul 2009 09:43:55 +0200 (MET DST)
address@hidden (Joerg Wunsch) wrote:

> You're perhaps confusing that with debugWIRE.  As debugWIRE is a
> one-wire protocol, it has to live with delays, caused by RC time
> constants of the circuitry.

Hmmm nope. We were very much discussing JTAG as this what I was
curious/interested about back then. However it was a long time ago so I
don't remember the details of the discussion... I do remember that I
was enquiring about debugging and also chaining. Maybe these use cases
do have some little delays that programming doesn't ? Anyway...

> ISP is basically the SPI engine of the controller, running in slave
> mode.

Ah ok, didn't know that.. assumed the ISP controller was something
complex enough to require a dedicated circuitry...

> As long as you've got JTAG-capable controllers, sure.  However, once
> you're using a smaller controller that only offers ISP, you have to
> use that.
> 
> Even though debugWIRE has its deficiencies (that are mostly due to its
> 1-wire bus technology), once you're faced with it, it's still much
> better than not being able to debug at all.

Well sure, if the part has no JTAG, I will have to do with whatever is
available on the chip ! ;-)

--
Vince