AVR-Chat

--- In AVR-Chat@yahoogroups.com, "k5atm" <k5atm@...> wrote:
 
> I purchased a Butterfly ... am a 
> bit confused ... the RISP cannot
> detect if the host (Butterfly) 
> has power ...

The Butterfly does not provide power at the ISP connector.  Yes, this 
is to protect the Butterfly's battery, which can only supply a few 
milliamps.

> I already have a (USB) RSIP MKII ...

If this does not take power from the ISP connector, it should work.  
It probably senses power (drawing only a tiny current), so you will 
have to link power from the Butterfly to pin 2, maybe via a resistor.

> I was wondering if I can safely fake 
> out the RSIP and make it think the
> host has power?

You must apply the same voltage as is powering the target because 
this voltage is used to set the signal drive levels of the programmer.

> Would a Butterfly / Butterfly carrier
> / RSIP combo work?

Yes.  This is exactly what the Butterfly Carrier is designed to do.

> ... a Butterfly / Butterfly carrier
> / Ecros Ice Cube combo will work just 
> fine.

Again, yes, this is what the Butterfly Carrier is designed to do.

> Will a Butterfly connected directly to
> an Ice Cube work?

No on this one.  The AVR ICE-Cube takes its power from the target and 
needs 10 to 20 mA.  The AVR Butterfly battery cannot supply this, so 
pin 7 of the JTAG header is unconnected and the AVR ICE-Cube won't 
light up.  If you buy an ICE-Cube, you might as well buy the 
Butterfly Carrier too, it will solve a lot of problems.  If you don't 
want to buy the carrier, you could use an external power source to 
fire up the ICE-Cube (negative at ground, 3 volts at pin 7 of the 
JTAG header).  But, be sure to supply a voltage within 0.5 volts of 
the battery voltage.  The AVR ICE-Cube has current limit resistors on 
all signals, so you won't permanently mess anything up if you go 
wrong, but it may not work.  It would probably be better to power 
both the AVR Butterfly and the ICE-Cube from external power, which is 
what the Butterfly Carrier does.

Graham.
Full disclosure - I am ECROS Technology