PIC24 OUT of ROM

richi-d · Joined: 28 Aug 2007 Posts: 106

PIC24FJ128GA108

The compiler shows this message:

"Out of ROM, A segment or the program is too large MAIN"

If I delete 1 line I´m at 74% of ROM. Why am I at the Limit?

Another question is how to bring something like that as a constant to RAM:

collink · Joined: 08 Jan 2010 Posts: 137 Location: Michigan

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

My best guess from what little you give us is that you have too much code in a single page. Each function, including main(), must fit in a single page of ROM. If your PIC (I'm not familiar with the PIC24FJ128GA108) has 4 pages, and one function takes 26% of total ROM, the program will never fit. If you trim that big function to 24%, suddenly the program fits and you have lots of ROM left.

Look for a big function and find a way to split it up.
_________________
The search for better is endless. Instead simply find very good and get the job done.

FvM · Joined: 27 Aug 2008 Posts: 2337 Location: Germany

Basically, the PIC24/dsPIC instruction set doesn't use pages. Branches with limited reach are relative, +/- 32k.

richi-d · Joined: 28 Aug 2007 Posts: 106

"Basically, the PIC24/dsPIC instruction set doesn't use pages."

Thats what I know, thats the reason why I´m wondering.

"Branches with limited reach are relative, +/- 32k."

Can you please explain?

richi-d · Joined: 28 Aug 2007 Posts: 106

richi-d · Joined: 28 Aug 2007 Posts: 106

The complete error message is:

richi-d · Joined: 28 Aug 2007 Posts: 106

I found in the program memory table following:

Code ends: 65320 (dec)
Memory end: 88054 (dec)

which is 65320/88054 = 0.74 = 74%

I´m wondering, the PIC has 128k.... what´s my error?

FvM · Joined: 27 Aug 2008 Posts: 2337 Location: Germany

You should show at least the magical line...

rnielsen · Joined: 23 Sep 2003 Posts: 852 Location: Utah

Not sure if this is your problem but...

The PIC's memory is constructed like a book. It has several pages that are used to store your code. Each page can only contain a certain amount of code though and will eventually fill up. The problem is that your main() or any other function must completely fit on a single page. It cannot carry over to the next page. Your main() appears to be too large to fit on a single page. To fix this, take a portion of your main() and create a function and call that function from main(). This will allow the newly created function to fit on another page and reduce the size of your main().

Clear as mud?

Ronald
-Never take a laxitive and a sleeping pill at the same time.

richi-d · Joined: 28 Aug 2007 Posts: 106

The PIC24FJ has no pages...

I fixed the problem: Took a PIC24FJ192 .... now there is enough space for the rest of the program.

Seems that the compiler is calculating wrong values for memory space!

FvM · Joined: 27 Aug 2008 Posts: 2337 Location: Germany

The above posted error message seems to indicate, that PCD is unable to assign code space across 64k address boundaries. As said, the PIC24 program memory space is basically continuous, except for table operations, so this limitation isn't actually justified. It would be easy however to split the respective code entity to make it fit a PIC24FJ128.