AVR-Chat

On Mar 19, 2008, at 6:41 PM, Graham Davies wrote:

> Even if you have to move to a smaller chip for production
> for cost reasons, for heavens sake develop on a chip with a debug
> interface.
>
> Mind you, by starting with the absolute cheapest thing out there  
> you've
> minimized the money you've wasted when you eventually see the light!


Several years ago I got my start in AVR designing a replacement for a  
product that used a COP8 that cost about $8 and was O.T.P.

Initial estimates at throwing away the existing assembly in favor of  
avr-gcc indicated 24k to 32k of code size. Our distributor priced the  
ATmega64L at less than $4 for 10k/year. I had a lot of big decisions  
to make and would have stuck to the ATmega64L for $4 even if a  
ATmega32 was free. If I had designed for a 16 or 32 and something  
bigger was needed the cost in redesign, re-qualification, and time-to- 
market was much greater than 10,000 chips at $4 each.

Of course you guessed it, when product shipped the code image was 14k.  
I don't believe they ever changed the chip to something cheaper. The  
fact the 64L works is not worth saving $1 for the expense of changing  
the PCB. That would change if they started shipping 100,000 units per  
year.

--
David Kelly N4HHE, dkelly@HiWAAY.net
========================================================================
Whom computers would destroy, they must first drive mad.