Nubie question: Programming ATMEL MEGA8

[[email protected]]

After looking over a lot of cool projects based on the ATMEL family of
microcontroller, I just bought a bunch of ATMGAG8-16PI's. I bought
these because I was under the impression these where very easy to play
with:

* On chip RC oscillator, no need for a crystal for simple stuff

* Lots of I/O pins with decent source and sink capacity - can light up
LED's directly

*A/D converter (might be fun to play with)

*No hardware programmer required - a few resistors hooked up to a PC's
printer port.

*Lots of free tools - assemblers, compilers, libraries etc.

Ok, so I have a bunch of the chips and I have downloaded and built up
the Linux AVR tools, the gcc cross compiler etc. I have also
downloaded the AVR Studio from ATMEL.

Now, here is the thing, it seems that the Linux AVR tools will support
the really simple "few resistor" type of programmer, whatever that is
called. I am not sure if the AVR Studio or any windows 2000/XP
software will support the same few resistor type programmer. I have
been looking around and I have found:

* A few of the few simple resistors and printer port based
programmers. The gotcha is just about all of them use different pins
on the printer port! They all use the same pins on the chip. Is
there not a standard for this? How do you know what will work with
what?

* A few that look like the above but that terminate in a dedicated
programming connection on the board with the micro. (JTAG?)

* A few of them that hang off the printer port and use different
amounts of old TTL logic between the printer port and the mico.

* A few of the above that go into the dedicated connection on the
board with the micro.

Are these guys cross compatible with the same programming software?
Being a big fan of making my own life easy, why would you add more
gunk between the two pieces?

* Then there is the breed that hangs off the serial port on a PC.

* Then there are the little dedicated "programmer" boards with the ZIF
sockets and what seems to be a lot more silicon in the programmer
itself.

So, can some kind soul tell me what the really cheep and easy
"resistors and the printer port" type programmer is called and point
me at some windows software that supports it (my linux box is a
desktop in another room, and I would like to be able to program these
from my notebook in the shop. The notebook runs XP and is unlikely to
change)

Also, if you can elaborate on what makes the different types of these
programmers "better" on "worse" then the other types. If I catch the
bug I suspect I will upgrade if the other types do something neat or
that can not be done with the Q&D ones.

Thanks in advance!

Matthew
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[Rich Webb]

After looking over a lot of cool projects based on the ATMEL family of
microcontroller, I just bought a bunch of ATMGAG8-16PI's. I bought
these because I was under the impression these where very easy to play
with:

* On chip RC oscillator, no need for a crystal for simple stuff

* Lots of I/O pins with decent source and sink capacity - can light up
LED's directly

*A/D converter (might be fun to play with)

*No hardware programmer required - a few resistors hooked up to a PC's
printer port.

*Lots of free tools - assemblers, compilers, libraries etc.

Ok, so I have a bunch of the chips and I have downloaded and built up
the Linux AVR tools, the gcc cross compiler etc. I have also
downloaded the AVR Studio from ATMEL.

Now, here is the thing, it seems that the Linux AVR tools will support
the really simple "few resistor" type of programmer, whatever that is
called. I am not sure if the AVR Studio or any windows 2000/XP
software will support the same few resistor type programmer. I have
been looking around and I have found:

IMHO your best bet would be to get the new AVRISP "MK II" programmer.
It's USB-based, so obsolescence shouldn't be an issue for a couple of
years at least. Relatively inexpensive.

There's support for it under Linux with AVRDUDE
http://www.bsdhome.com/avrdude/. That page (and links from it) also
describe some roll-yer-own programmers.

 

[[email protected]]

IMHO your best bet would be to get the new AVRISP "MK II" programmer.
It's USB-based, so obsolescence shouldn't be an issue for a couple of
years at least. Relatively inexpensive.

There's support for it under Linux with AVRDUDE
http://www.bsdhome.com/avrdude/. That page (and links from it) also
describe some roll-yer-own programmers.

I will check out avrdude and see what he has. I am looking to do this
as on the cheep as I can, so I am really looking for better into on
the "few resistors hanging from the printer port" at least to get
started. One of the really big things in favoe of these chips is that
you do not need much to program them. Ideally this would be free out
of junkbox parts.

Thanks again for the pointer to avrdude though, I will see what he has
to offer.

--Matthew


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[Rich Webb]

I will check out avrdude and see what he has. I am looking to do this
as on the cheep as I can, so I am really looking for better into on
the "few resistors hanging from the printer port" at least to get
started. One of the really big things in favoe of these chips is that
you do not need much to program them. Ideally this would be free out
of junkbox parts.

Nothing wrong with that approach, of course, and it can be a fun
project. The spec programmer, though, is only about $30 and takes away
one variable when you're grinding your teeth wondering why the $%!&*
thing won't program. ;-)

One hint for the ATmega-series: they come from the factory with the
fuses set to run from the internal RC oscillator. On the one hand, this
is a good thing since non-timer-critical applications can install and
program the chip without having to have a clock source.

On the other hand, it's REALLY easy to forget this and wonder why a
brand new chip refuses to program. The ISP freq needs to be <= 1/4 the
clock speed of the device to be programmed and some of the family have
RCs at 1 MHz.