SMILEY’S WORKSHOP ☺
■ FIGURE 8. AVR Tools Help.
■ FIGURE 9. ISP connections.
BeAVR then we will use that bootloader for future
programming efforts. We are going to go the cheapo route
and directly wire the Dragon ISP port to the BeAVR SPI port.
[BTW, SPI is not a typo. The ISP (In System Programming)
goes through the SPI (Serial Peripheral Interface).]
I happened to have a six-wire IDC cable lying around
and a six-pin male header, so I chose the method shown.
Before getting started on this, I suggest you open the
AVRStudio Help\AVR Tools (Figure 8), find the section on the
Dragon, and read it. I summarize some of the more relevant
stuff for our venture. In Workshop 21, we were introduced
to AVRStudio and WinAVR. You can get them at www.
■ FIGURE 10.
Talk about a bad hair day ... how would you like to
have to comb out that curly top? Our Medusa isn’t quite
as bad, but let me tell you up front, it will get ugly before
it gets pretty, and it might just turn you into stone in the
process. You will need to solder six 4” AWG 22 solid core
wires to the base of a 2 x 3 0.1” male header (without
short-circuiting them — and that is a trick!) as shown in
Figure 9. Then, you will want to
add “Scotch” tape (actually, any
nationality tape will do) flags to
each wire and mark them with the
SPI signal names as shown in
Figure 10. I suggest you get a
multimeter and check continuity
for each wire. Make sure it
conforms to the signal as it starts at
the Dragon, passes through the
Medusa, then arrives at the BeAVR.
Figure 11 shows the finished rat’s
nest. Let’s be honest, I didn’t wire
this correctly the first time I tried,
but eventually got it right. Cheap
has a price.
allows you to use
including the Dragon.
Let’s do this cookbook style. Click on the ‘Display the
‘Connect’ Dialog’ as shown in Figure 12.
In the resulting ‘Select AVR Programmer’ window
shown in Figure 13, highlight the AVR Dragon and USB.
Open the ‘Main’ tab as shown in Figure 14 and push
the ‘Read Signature’ button. If you see the three hex
numbers shown in the window and it says ‘Signature
matches selected device’, then you are in business. If not
… something’s probably not right about your hardware
Open the ‘Fuse’ tab as shown in Figure 15. Click the
boxes and set the settings EXACTLY as shown in the
picture. This is where you get the opportunity to turn your
ATmega644 into a brick if you get it wrong. (Bricked AVRs
can be unbricked with high voltage programming which is
— as they say — ‘a whole ‘nuther topic.)
Finally, open the ‘Program’ tab as shown in Figure 16
and browse to find the input hex file (which should be the
hex you got from the
■ FIGURE 11. Dragon Medusa
■ FIGURE 13. Select AVR Programmer.
■ FIGURE 14. AVR Programmer - Main Tab.
■ FIGURE 12. AVRStudio Display
Using AVRStudio to
Upload the Bootloader
The AVRStudio Programming
Front-End — as AVRStudio calls it —
May 2010 73