AVR-Chat

I am new to the world of Atmel chips.  I am a long time PIC 
programmer looking to expand my horizons.

I purchased a Butterfly with a specific project in mind but I am a 
bit confused and looking through the archives did not help much. I am 
using AVR Studio 4.13 and WinAVR.

I would like to avoid using the bootloader to load my code.  I am 
using the RS232 port and swaping cables every time I want to load 
code is a pain.

As far as I can tell I cannot use the AVR RISP to program the 
Butterfly.  Apparently the RISP cannot detect if the host (Butterfly) 
has power -- a feature to protect the Butterfly's battery?  Since I 
already have a (USB) RSIP MKII I was wondering if I can safely fake 
out the RSIP and make it think the host has power?  Would a 
Butterfly / Butterfly carrier / RSIP combo work?
 
I am also a bit confused on JTAG debuggers.  It appears that a 
Butterfly / Butterfly carrier / Ecros Ice Cube combo will work just 
fine.  Will a Butterfly connected directly to an Ice Cube work? -- or 
do I need to provide external power to the Butterfly for the Ice Cube 
to work.

Thanks in advance for any help on such a basic question.

-Mike

At 04:03 PM 8/01/2008, you wrote:
>Apparently the RISP cannot detect if the host (Butterfly)
>has power -- a feature to protect the Butterfly's battery?

If you have an AVRISP MK2, the REAL Atmel unit, ISP should
work provided that the Butterfly's battery is in good condition.

Regards

John Samperi

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--- 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