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hello!

sorry for disturbing...

i am now doing a project using MC PIC 18F4220. it is actually a fiber
optics project, but i've been assigned to complete the receiver part
which includes front-end, digital signal processing and other two more
parts. i'm doing only the digital signal processing part and i need to
use PIC18F4220.

actually, my level of electronics is very poor. after reading through
the Microchip PIC 18F4220 datasheet, i don't even understand even 5%
of it.

i simply explain my project like this:

- the digital signal processing part (DSP) will receive signal from
the front-end (FE).
- because this is a multilevel transmission system project, for
assumption and example, there will be 4 signals coming from FE to DSP.
- by using Non-Return Zero (NRZ) modulation, these 4 signals will be
combined and transmitted into PIC18F4220.
- through the PIC18F4220, the signal will be processed and the output
will be 4 signals which are identical to the original signals.

i really need help for this project. there are 40 pins on PIC18F4220,
and AT LEAST, can anybody please help me to show at what pin...
(a) to insert A signal (one signal) to the PIC18F4220?
(b) to insert 4 signals to the PIC18F4220?
(c) to measure the output of (a)?
(d) to measure the ouput of (b)?

i really need help from all of you guys and i really appreciate it.
thanx a lot!


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Hi All,

Can we embedded linux OS on the PIC Chips.

Thx!

Ashan



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Pretty unlikely - The PIC does not have the resources needed to run that
OS. There are other RT and multitasking OS's available for the PIC however.

DLC

Ashan Abeysekara wrote:
> Hi All,
>
> Can we embedded linux OS on the PIC Chips.
>
> Thx!
>
> Ashan
>

--
---------------------------------------
Dennis Clark TTT Enterprises
---------------------------------------



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Hiya-

As mentioned in the earlier post, the PICs do not have the hardware
resources to effectively port a linux kernel to it. Specifically,
linux really needs a memory management unit for it to function with
any sort of speed. uClinux, specifically written to be very similar
to linux was written for those class of smaller processors that
do no have an MMU. However, even uClinux requires much more RAM
than the PIC has on chip and interfacing to external RAM is not
a PIC's strong suit.

I would humbly suggest that if you want to persue linux in an
embedded system, and you are no locked into an existing design,
you might look at some of the ARM architectures available from
various vendors. Linux (or uClinux) with the application busybox
can yield some very small footprint machines, but IMHO, the PIC
is just way too small. In fact, context switching, due to the
limited amount of RAM, makes any sort of multitasking OS on the
PIC and interesting exercise. I'm sure that it could be done,
but I've accessed external memory on the PIC and one pays a
high price in software overhead to do so.

So, I suggest a larger CPU. BTW, the uClinux project mentioned
above can be found at:

http://www.uclinux.org/index.html

Cheers,

Rich S.

--- In p...@yahoogroups.com, Ashan Abeysekara
wrote:
>
> Hi All,
>
> Can we embedded linux OS on the PIC Chips.
>
> Thx!
>
> Ashan
>



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