Re: [avr-libc-dev] [task #3693] Add new devices: mega 640-1280-1281-2560-2561

[Marek Michalkiewicz]

On Tue, Mar 15, 2005 at 04:46:37PM -0500, Paul Schlie wrote:

> - only by conveniently ignoring that possibility; as Atmel seems to
>   have already positioned the arm family of uC's to likely satisfy
>   broader needs beyond these devices.

Actually, I'm a bit surprised Atmel introduced ATmega256x when such
strong competition from 32-bit microcontrollers (much cheaper today
than they used to be a few years ago) exists.  Some of them, despite
low cost, can (with enough external memory) run Linux.

<offtopic> No kidding, chances are high that if you buy a cheap
SOHO router or WLAN access point, for about $50 you get a MIPS-based
development board with Ethernet (sometimes a few ports), sometimes
USB, 2MB flash, 16MB SDRAM and Linux inside - see:

http://rtl8181.sourceforge.net/
http://vlad.org.ua/adm5120/

Of course, the low cost is possible because of mass production in
Taiwan (you can't make your own board so cheap), but the boards can
find interesting uses if you replace the firmware with your own.
</offtopic>

> > Sorry, there's no getting around the fact that the program
> > counter can be more than 16 bits now.

OK, back on topic:

Shifting left by 6 (128-byte alignment) would allow supporting the
full 8 MB address space possible with the AVR instruction set.
Inefficient, but might still be acceptable unless your program has
a lot of very small functions.  Making pointers larger than 16 bits
might make the code much less efficient, too.

Marek