Subject:
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Re: mindstorms NXT and memory
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 9 Jan 2006 15:41:48 GMT
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Viewed:
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9114 times
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On Mon, 9 Jan 2006 14:59:51 GMT
"Kevin L. Clague" <kevin_clague@yahoo.com> wrote:
> Well, *any* machine is harder to program at machine code level. If
> you mean assembly, I diagree. I spent the first 18 years of my
> career on IBM mainframes, and the last 5 on SPARC machines. They
> each have their advantages and disadvantage from a programming
> perspective. CISC machines have less registers (including Intel X86)
> and are harder to program because of this.
>
> ARM7 has a nice number of registers that is much larger than those in
> an Intel box.
That could have something to do with the fact that the x86 architecture
is extremely low on registers, pretty much all of which have special
functions (CX for counting, BX for addressing, AX:DX for
multiplications, SI+DI for memory copying). Compare this to the 68k
family, a CISC platform which starts out with 8 address and 8 data
registers. I've only seen fewer than the x86 on the 6800, which is
remarkable in that it has about 3 registers. That was tight enough that
GCC *couldn't* generate code for it, instead the gcc 68hc11 target
actually uses the low area of RAM to emulate registers (which isn't
that far off, as the 6800 typically contains that ram on-chip and has a
special addressing mode for them).
The H8 in the RCX is a 16-bit CPU, and couldn't really have worked with
much more memory than the RCX had - the 32KiB included was impressive,
and covers half the addressable space.
It also seems rather clear to me that Lego is operating on a tight
budget currently, so there was no real option to toss in an "expanded"
variant yet. We're half a year from product launch, and already people
worry about the product *line* being limited?
Bluetooth, protocol wise, is a bit of a mix between IrDA and USB. It
was not intended for storage devices, and in fact a device like a usb
flash drive would be complicated for the NXT to access - you'd be
dealing with file systems and block I/O. The same issues would be
associated with all the other memory card types.
Bluetooth networking is essentially PPP based, and as with the RCX the
protocol would probably be considered overkill. There's no need to run
IP or Ethernet when the lower level protocol already gives us
addressing and discovery.
We can expect the base library to be limited to the minimum necessary,
which would be just serial-style connections. This would straight away
give communication with phones, computers, GPS receivers and other NXTs.
The particular improvements over the IR sported by the RCX are
reliability, speed, and multiple connections. That last bit is the one
we might not see much of in the official software, but there *will* be
others.
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Message has 1 Reply:
 | | Re: mindstorms NXT and memory
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| Another possibility for the grinder bunch is seeing if the onboard flash chip can be SMT desoldered and replaced with a larger capacity model with the same pinout. I'm assuming there will be various third-party OSes to run on NXT pretty quickly, so (...) (18 years ago, 9-Jan-06, to lugnet.robotics)
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Message is in Reply To:
| | Re: mindstorms NXT and memory
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| (...) Well, *any* machine is harder to program at machine code level. If you mean assembly, I diagree. I spent the first 18 years of my career on IBM mainframes, and the last 5 on SPARC machines. They each have their advantages and disadvantage from (...) (18 years ago, 9-Jan-06, to lugnet.robotics)
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