Searching \ for ' [PIC] how to run a program in a pic from' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/microchip/devices.htm?key=pic
Search entire site for: 'how to run a program in a pic from'.

No exact or substring matches. trying for part
PICList Thread
'[PICLIST] [PIC] how to run a program in a pic from'
2001\01\02@170724 by coldark

picon face
hi all, [PIC] how to run a program in a pic from a external memory
i think that is usen info of PCL of pic 16f84 if any can do or
have ready . please explain me

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\01\02@181106 by Byron A Jeff

face picon face
>
> hi all, [PIC] how to run a program in a pic from a external memory
> i think that is usen info of PCL of pic 16f84 if any can do or
> have ready . please explain me

Nothing to explain. It cannot be done. Only the PIC 17XX and 18XX families
have external memory interfaces.

Typically what is done is using a threaded interpreted bytecode where the
bytecode is read from the external memory and this it's decoded and executed
by the threaded interpreter code that in the program memory in the chip.

It has its uses but is generally a lot slower than running the program onchip.
The primary reason is that the external storage device will have a serial
interface (like a EEPROM) and will take a lot of time to simply pull the
data in to be interpreted.

I have such an interpreter in cold storage waiting for some TLC to get
together. Now that I have revivied my development setup with gpasm/gpsim
coupled with linwload and wloader running on a 16F877, I plan to spend some
time getting my NPCI bytecode interpreter useful enough to release. And
finally figuring out a license I can live with...

So now that you know, why not tell us what it is that you're trying to do.
There may be another useful path that can be attained if we knew what
the external program memory was required for...

BAJ

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\01\02@184458 by Herbert Graf

flavicon
face
> hi all, [PIC] how to run a program in a pic from a external memory
> i think that is usen info of PCL of pic 16f84 if any can do or
> have ready . please explain me

    That can not be done with a 16x series PIC. (well, technically it could
be done if you programmed the PIC to be a language interpreter like the
Basic Stamp). TTYL

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\01\03@133105 by John Mullan

picon face
I was under the impression that this could be done with a 16C874?  I read
that it can modify it's own program memory.  Given that, you could use a
parallel or serial EPROM, read in overlay code then execute it?

Am I mistaken??

John


{Original Message removed}

2001\01\03@134639 by M. Adam Davis

flavicon
face
Well...  You *could*...  But /why/???  If you need more code space, use an
'f877 (8K).  If you need more than that then you should look at what other
manufacturers are producing, or take a really good look at what you are
doing, and why you think it needs to be done this way.

The code flash is only guranteed for 1000 writes/erases (anecdotal
evidence seems to show that it may last significantly longer - but I
wouldn't try it, it would be too much of a hassle to deal with).  If you
only write the code from the external memory to the chip once a week or so
then I can see you doing this, but it seems like a terrible kluge.  What
problem are you trying to solve by having some of the program stored
externally?

-Adam

John Mullan wrote:
>
> I was under the impression that this could be done with a 16C874?  I read
> that it can modify it's own program memory.  Given that, you could use a
> parallel or serial EPROM, read in overlay code then execute it?
>
> Am I mistaken??
>
> John
>
> {Original Message removed}

2001\01\03@134645 by mike

flavicon
face
On Wed, 3 Jan 2001 13:30:17 -0500, you wrote:

>I was under the impression that this could be done with a 16C874?  I read
>that it can modify it's own program memory.  Given that, you could use a
>parallel or serial EPROM, read in overlay code then execute it?
>
>Am I mistaken??
..although you could do this,  the flash has limited write cycles
(1000?) and programming is rather slow.
--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2001\01\03@145038 by Byron A Jeff

face picon face
>
> I was under the impression that this could be done with a 16C874?  I read
> that it can modify it's own program memory.  Given that, you could use a
> parallel or serial EPROM, read in overlay code then execute it?
>
> Am I mistaken??

No you are not mistaken. However it doesn't fit the original specification
because the program is run from internal memory as normal.

My original statement stands. There is no way to run code directly and
external on a 16 family part.

BAJ
>
> John
>
>
> {Original Message removed}

More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...