On Mon, 21 Jul 2008 08:55:29 -0400, Rich Webb posted:

> On Sun, 20 Jul 2008 21:55:10 -0600, Ron Ford <r...@nowhere.net> wrote:
> 
>>It would certainly seem that Atmel is the norm for AVR RISC controllers.
>>The link didn't have any information about prices.  While it looked like
>>the chips themselves are a few bucks, am I correct to think that I would
>>also need a "workbench?"
>>
>>AVR Startup Package
>>• JTAGICE-MK2
>>• ATSK500+501
>>• IAR Kickstart Workbench
>>Price € 339,00*
>>• JLINK JTag ICE (unlimited)
>>• SAM7S64-EK
>>• IAR Kickstart Workbench
>>Price € 250,00*
>>
>>My question is what is the minumum cost of entry?  I saw other numbers that
>>were ten times as much.
> 
> Minimum cost depends very much on what's hiding in your junk er ah spare
> parts bin and how much you're willing/able to spend the time to roll
> your own.
> 
> A minimal startup would need just a chip, breadboard (plus power,
> connectors and so on), an in-system programmer, and the free AVR Studio
> available from Atmel. There's also WinAVR (a gcc port)
> http://winavr.sourceforge.net/ that plays well with Studio.
> 
> The in-system programmer is within the capabilities of end-users to
> build but the standard AVRISP Mk2 (USB interface) is only US$36 and that
> removes one variable when first starting out. Add an ATmega168 (16K
> flash, 28-pin DIP) for another US$4 and you're good to go.
> 
> The STK500 is a stand-in for a breadboard + ISP, having sockets for all
> of the DIP-flavored AVRs. Its programming headers can also be used to
> program devices off-board (e.g., on a breadboard).
> 
> I'm not a huge fan of ICEs and they're certainly not necessary for a
> minimal startup system. The AVRISP is quite sufficient to load code into
> a device and get it running.
> 
> One caveat here: Most (all?) AVRs with internal RC oscillators come from
> the factory with their fuses set to use the RC as the system clock,
> typically at 1 MHz. The ISP programming clock should be set to no more
> than 1/4 of the devices clock speed. If one doesn't realize that the
> device is running from the internal oscillator, instead of the 14 MHz
> xtal that's hooked up, the chip can appear to be faulty. The solution,
> of course, is to lower the ISP speed to below 250 KHz in order to
> communicate with the device to set the fuses to use the external
> clock/crystal; after that, the ISP speed can be set higher if desired.

I'd like to say that I understood everything you wrote here, but it
wouldn't be true.  Please don't confuse my misapprehension with
ingratitude.
 
> On the compiler side, I've been using Imagecraft for years and am quite
> happy with them. They also offer an AVR starter kit (compiler included)
> that may interest you. http://www.imagecraft.com
> 
> http://www.avrfreaks.net/ is a super resource with links to other
> compilers, kits, tools, ...
> 
> One last thing. The SAM7 chips are ARM7 devices (32-bits). They're quite
> nice as well but do be aware that it's a different family.

Thanks again for your generous response, Rich.  I'm downloading WINAVR and
will ask a more-focussed question on a new thread.
-- 
Let's not burn the universities yet. After all, the damage they do might be
worse.
H. L. Mencken

On Mon, 21 Jul 2008 19:44:23 -0600, Ron Ford <r...@nowhere.net> wrote:

>On Mon, 21 Jul 2008 08:55:29 -0400, Rich Webb posted:

>> One caveat here: Most (all?) AVRs with internal RC oscillators come from
>> the factory with their fuses set to use the RC as the system clock,
>> typically at 1 MHz. The ISP programming clock should be set to no more
>> than 1/4 of the devices clock speed. If one doesn't realize that the
>> device is running from the internal oscillator, instead of the 14 MHz
>> xtal that's hooked up, the chip can appear to be faulty. The solution,
>> of course, is to lower the ISP speed to below 250 KHz in order to
>> communicate with the device to set the fuses to use the external
>> clock/crystal; after that, the ISP speed can be set higher if desired.
>
>I'd like to say that I understood everything you wrote here, but it
>wouldn't be true.  Please don't confuse my misapprehension with
>ingratitude.

Heh. No worries, just tuck it in the back of your mind. One day you'll
be trying to program a brand new AVR chip with the same setup that's
worked flawlessly for your "lab rat" development chip and then wonder
WTF why the new chip isn't even recognized by the programmer.  ;-)

-- 
Rich Webb     Norfolk, VA

Ron Ford wrote:

> Then I'm in.  Do you have a header board?

No, I have just some chips, but you can buy some:

http://www.sparkfun.com/commerce/advanced_search_result.php?keywords=avr+header&x=0&y=0

-- 
Frank Buss, f...@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de