Run code outside the flash

Bilal · Joined: 24 Apr 2010 Posts: 75 Location: Islamabad

Hi, did anyone try to run a code outside the flash by using PIC? Maybe from eeprom or sd card.
(its not about copy the code from external source and then run it).
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Gabriel · Joined: 03 Aug 2009 Posts: 1067 Location: Panama

get a bigger PIC.

;)
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CCS PCM 5.078 & CCS PCH 5.093

temtronic · Posted: Sat Jun 02, 2012 12:25 pm

Yes, technically possible but reality says buy a bigger/more powerful PIC.
If you add the cost of external EEPROM or SD interface(and card) it will exceed the cost of a bigger PIC !
Also overall performance will be less due to the constant reads to the external memory.
BASIC Stamps kinda work that way but unless you have a LOT of time on your hands.....buy a bigger PIC, reduce your code,optimize functions, etc.

Ttelmah · Joined: 11 Mar 2010 Posts: 19337

Basically, the PIC only runs code in it's own memory.
Some larger PIC's allow external memory to be added to this area.
Other choice is to do what the Stamp's do,and have the code in the PIC form an interpreter, which then reads it's 'code' from an external memory. However it doesn't then directly 'run' this code.

Best Wishes

Bilal · Joined: 24 Apr 2010 Posts: 75 Location: Islamabad

Hi i have watched a video
http://www.youtube.com/watch?v=5h28QiYlXe8&feature=related

guy did this with other controller

can i do the same with PIC??? I have some PICs like
PIC16F877A with external EEPROM
PIC18F4550 with external sdcard
and PIC32MX775F512H with external sdcard
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Ttelmah · Joined: 11 Mar 2010 Posts: 19337

This is exactly what the STAMP's do.
Basically you are not running Arduino code, or PIC code, but code written in the language that the code in the host processor then understands.
Yes, you can do this. I'd say something like a couple of months careful work for a reasonable programmer would give a working program in the PIC, plus then the same again, or a bit more, to write the PC code to generate the byte patterns to store in the memory. In all, possibly about six months work.
Alternatively, buy the STAMP code which already exists.
Understand that with this flexibility comes a speed cost.

Best Wishes

temtronic · Posted: Sun Jun 03, 2012 10:10 am

yup all it takes is time or money.
time..T's right MINIMUN of 6 months..10-12 hour days, 7 days a week....

money..buy product off the shelf that someone else has created.

Your choice...I've done both...have decided to cut CCS C code as it's easier,faster and FAR easier to debug...

J