Using an AVR Butterfly as an input/display.

I have a project that needs a small display and input and I also have an AVR butterfly lying around.http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3146 I would need to be able to reprogram the butterfly and talk back and forth with it over serial.

I don't want to wander aound in a swamp though so I wonder if anyone has done this. The butterfly expects to be programmed over RS232 serial which I don't have and it runs at 3V. I was thinking of using ICSP to program it but my pololu usb programmer won't work down that low.

I assume that, if i can program it, I can load soft serial in it so i just ignore its rs232 pins. I don't think level shifting from the arduino to 3.3 would be too bad, probably only needed on the butterfly's input.

so, just throwing this out there looking for hints while I look at my avr dragon doc and see if it will program a 3v target.

The butterfly expects to be programmed over RS232 serial which I don't have and it runs at 3V. I was thinking of using ICSP to program it but my pololu usb programmer won't work down that low.

I've been programming an ATtiny13 running off 2 AA batteries using my Uno. I use a pair of voltage dividers for SCK and MOSI. For MISO, I use two transistors to raise the voltage (there is very likely a way to do it with one transistor). For RESET, a simple (but very important) modification to Arduino ISP makes it float or sink rather than source or sink.

[quote author=Coding Badly link=topic=74041.msg557548#msg557548 date=1317532394]

The butterfly expects to be programmed over RS232 serial which I don't have and it runs at 3V. I was thinking of using ICSP to program it but my pololu usb programmer won't work down that low.

I've been programming an ATtiny13 running off 2 AA batteries using my Uno. I use a pair of voltage dividers for SCK and MOSI. For MISO, I use two transistors to raise the voltage (there is very likely a way to do it with one transistor). For RESET, a simple (but very important) modification to Arduino ISP makes it float or sink rather than source or sink.

[/quote] Ok thank you. I find that the dragon will work down to 3v and i found a tutorial on using its JTAG with the butterfly on the atmel site - another bunch of stuff i don't normally use. At the moment I'm trying to see if it will work with a cheap USB serial converter.

this is probably more trouble than it's worth. I can get the serial working somewhat but the bootloader doesn't seem to want to play. I'll go with my own lcd and a couple of buttons. It won't be as pretty but I'll know what I'm doing!

Never one to let a bad idea go, I was able to get this working by supplying external power and following directions from http://www.dwelch.com/avr/

Still too much trouble for the 5 character display though. I'll roll my own for now but if i run out of progmem I'll have this to fall back on.

Hello,

I am thinking to do the same. I have one Butterfly programmed with the GCC -compiled port and I want to use it as LCD output /Joystick Input for my Arduino Mega. I am also planning the communication via serial. Did you finally made it?

According programming, I have an STK500 so I can program the butterfly through the ISP connectors.