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- Subject: Re: hardware + Lua resources
- From: KHMan <keinhong@...>
- Date: Wed, 29 Dec 2010 13:51:04 +0800
On 12/29/2010 1:03 PM, Javier Guerra Giraldez wrote:
On Tue, Dec 28, 2010 at 10:40 PM, KHMan wrote:
On 12/29/2010 11:36 AM, Javier Guerra Giraldez wrote:
sorry to disappoint, but PIC (even in the '32 family) doesn't have
anything to do with the MIPS architecture. I guess the mixup is
because in their literature they repeat again and again the "highest
You sure? Go look at some datasheets and come back when you've finished.
right, i was wong.
it turns out that PIC32 is a low-end MIPS core with a boatload of
PIC-style on-chip peripherals and no PIC core anywhere.
still, it doesn't have any external bus interface (no, GPIO pins
doesn't count. i've done that on smaller PICs, but it makes external
memory look like storage devices, not RAM); so any port would be
limited to what inner memory can hold.
Patrick in the original post mentioned Logitech keyboards -- which
for many of the high-end keyboards would use something like a
one-chip solution like PIC32. Nobody sane will put in extra memory
chips in such products, unless for a high-end low volume prestige
product to make the other SKUs more palatable.
PIC32MX695F512H, for instance, has 128KB SRAM, and this is
certainly within the specs of the types of ARM chips that eLua and
related projects have been targeting.
So the kinds of chips mooted by Ivan is certainly relevant. The
list in the past indeed talked about implementations of Lua on
chips with less memory than that. Let us just call them high-end
and low-end and both are quite relevant in this discussion.
OTOH, MIPS is a real 32bit ISA, targeted by real C compilers (gcc
among them). In fact, even i own a MIPS-based router running a full
Linux (OpenWrt), complete with a Lua interpreter, and i consider
myself quite lacking gadgetwise.
Being a practical engineer, I sniff at your use of the word "real"
twice in the above. Amusing. No offense. *rolls my eyes*
In any case, give the handphone wars a few years and many will
adopt what is already being done in many handphones -- stack >=2
chips in one package -- most likely the processor SoC and the RAM,
and leave an external interface to the Flash chips. The lines of
traditional memory buses is being blurred very fast.
So, external memory buses are simply an implementation detail that
depends on your particular product. In other words, when I use a
one-chip solution, I don't consider myself any less macho.
This is getting to OT, so I'll try to end this here and let the
thread steer itself back to eLua and related stuff.
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia