Which MCU has these features?

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The linux-tiny project has reduced the linux kernel down to ~300kb,
able to run in 2MB of RAM. With uclibc and busyboy, I can have a
running system in under 2MB of flash.

So I started looking for ARM MCUs, a few have 2MB flash onboard, one
from atmel has 2MB SRAM onboard, but I couldnt find any that has both.
ARMs no limitation, but it shouldnt be as inefficient as x86 with
power, and should have at least 2MB (S)RAM and 2MB flash onboard. I
know its not a stretch to add a 2MB or even 16MB (S/SD)RAM chip to it,
but it would be an accomplishment to run this OS on one chip.

Is there a dragonball, ppc, mips or sh3-based chip out there with both
2MB RAM and 2MB flash onboard?

Re: Which MCU has these features?
Ghazan Haider said
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This isn't any of the micros you named, but take a look anyway:

http://developer.axis.com/products/mcm/etrax_mcm_4+16_low.pdf


I'm not connected with the company and I've never used it - just looks
like an interesting option.



Casey

Re: Which MCU has these features?
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Look at Intel's XScale variants, they have stacked die solutions that
have more than you ask for.
TI was talking about a similar thing and may have that in their
OMAP line.
-jg


Re: Which MCU has these features?
: The linux-tiny project has reduced the linux kernel down to ~300kb,
: able to run in 2MB of RAM. With uclibc and busyboy, I can have a
: running system in under 2MB of flash.

[SNIP]

: Is there a dragonball, ppc, mips or sh3-based chip out there with both
: 2MB RAM and 2MB flash onboard?

Only as an "Multi Chip Module (MCM)" in the form factor of a BGA:

  http://developer.axis.com/products/mcm /

But then again, Axis has already ported Linux onto this module and
they are shipping products (I.e. Networked cameras) with it...


--
  ******************************************************
  Never ever underestimate the power of human stupidity.
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Re: Which MCU has these features?
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I've been aiming for low-cost and low-power. If the cost and power are
low enough its acceptable (given of course no glue-logic required).
I'd also underclock the system for lower power. The intention is to
run the system on solar power like larger calculators.

I should've also mentioned an LCD interface is preferred, although I
could with enough IO pins implement that, so there should be a minimum
of 8 pins for the LCD.

DIP, BGP, all acceptable, and in fact a smaller size will also be
preferrable, but with all these aside, is there any MCU that runs
either linux or netbsd with 2MB R/2MB F ?

Re: Which MCU has these features?
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Not on a single die. A micro core like ARM, MIPS, etc requires several
metal layers on top of the chip (interconnects) due to its complexity.
A flash or RAM array is a flat 2D array of cells which does not
require the extra metal layers. When you put both memory and CPU on a
single die, you save on bonding and packaging costs. But on the other
hand the memory section of the die is much more costly (in dollars per
mm2) than it would be if manufactured separately, because it had to go
through those extra process steps even though they weren't laying
anything down in those areas. As the size of the memory area grows, a
break-even point is approached. I'm told that the break-even point is
between 512K and 1M.

So it is not cost-effective (external chip vs. on-die memory) to make
large memories on the same die as the processor. Once you cross-the
break-even point mentioned above, the only options are stacked modules
or side-by-side hybrids. These devices are undesirable due to poor
vibration resistance and EMI issues.

Re: Which MCU has these features?
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How long have you wondered if you were told that the break even point
is between 512k and 1m?

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A poor beauty finds more lovers than husbands.

--
Lady Chatterly

"A turing test is not infallible....." -- The Poster With The Longest
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Re: Which MCU has these features?
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Not so much worried about cost as power. I'm hoping more for 90nm
process-ARMs, and the reduced power with the ram and flash onboard.
Space isnt an issue either.

Your comments however made this issue very clear to me. Thanks.

Re: Which MCU has these features?
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You might not be, but the chip vendors are! Unless there are special
app-specific constraints, they won't make an integrated device that is
more expensive than multidie solutions...

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