About the memory in PIC18F25k50

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maniac84

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I faced 'section '.udata_xxx.o' can not fit the section' error and after searching through the net, we actually can create objects larger than 256 Bytes by configure the linker files like below:

Code: 
DATABANK   NAME=gpr1       START=0x100             END=0x1FF
DATABANK   NAME=gpr2       START=0x200             END=0x2FF
DATABANK   NAME=gpr3       START=0x300             END=0x3FF
DATABANK   NAME=gpr4       START=0x400             END=0x4FF
DATABANK   NAME=gpr5       START=0x500             END=0x5FF

These 256-byte regions need to be combined into larger regions to fit the new sections:

DATABANK  NAME=large_udata  START=0x100  END=0x389  PROTECTED
DATABANK  NAME=large_idata  START=0x38A  END=0x519  PROTECTED
DATABANK  NAME=gpr5         START=0x51A  END=0x5FF

If I don't put the word PROTECTED, it can compile. But everytime I put the word PROTECTED, the 'cannot fit error' occurs again. Does this means my firmware really have no memory already?
 

xpress_embedo said:
The Optional Keyword PROTECTED is used to identify and area in RAM, that can be assigned only to a variable that are specifically identified in a source code.
Click to expand...

I know. that's what I am trying to do. fixing the area for my variable.
but when I put 'protected' the 'does not fit error' wil appear after I compile. y?
 

hello,

have a look on this example for a 18F46K22
very easy with this MCU because a lot of RAM available..
i reserve 512 bytes RAM for a nokia LCD caracteres table..
don't forget, you can not use all of RAM databank, because the C compiler will use some udata or idtata area..

declaration in my C programm
Code: 
#pragma udata NokiaBank // 2 bank = 512 bytes


const char table[480] = {
0x00,0x00,0x00,0x00,0x00, // 20 space ASCII table for NOKIA LCD: 96 rows * 5 shorts= 480 shorts
0x00,0x00,0x5f,0x00,0x00, // 21 ! Note that this is the same set of codes for character you 
0x00,0x07,0x00,0x07,0x00, // 22 " would find on a HD44780 based character LCD.  
0x14,0x7f,0x14,0x7f,0x14, // 23 # Also, given the size of the LCD (84 pixels by 48 pixels), 
0x24,0x2a,0x7f,0x2a,0x12, // 24 $ the maximum number of characters per row is only 14.  
0x23,0x13,0x08,0x64,0x62, // 25 % 
0x36,0x49,0x55,0x22,0x50, // 26 & 
0x00,0x05,0x03,0x00,0x00, // 27 ' 
0x00,0x1c,0x22,0x41,0x00, // 28 ( 
... etc ....
0x10,0x08,0x08,0x10,0x08, // 7e Right Arrow -> 
0x78,0x46,0x41,0x46,0x78}; // 7f Left Arrow <-
#pragma

and the modified linker file :
Code: 
// File: 18f46k22_g.lkr
// Generic linker script for the PIC18F46K22 processor

#DEFINE _CODEEND _DEBUGCODESTART - 1
#DEFINE _CEND _CODEEND + _DEBUGCODELEN
#DEFINE _DATAEND _DEBUGDATASTART - 1
#DEFINE _DEND _DATAEND + _DEBUGDATALEN

LIBPATH .

#IFDEF _CRUNTIME
  #IFDEF _EXTENDEDMODE
    FILES c018i_e.o
    FILES clib_e.lib
    FILES p18f46k22_e.lib

  #ELSE
    FILES c018i.o
    FILES clib.lib
    FILES p18f46k22.lib
  #FI

#FI

#IFDEF _DEBUGCODESTART
  CODEPAGE   NAME=page       START=0x0               END=_CODEEND
  CODEPAGE   NAME=debug      START=_DEBUGCODESTART   END=_CEND        PROTECTED
#ELSE
  CODEPAGE   NAME=page       START=0x0               END=0xFFFF
#FI

CODEPAGE   NAME=idlocs     START=0x200000          END=0x200007       PROTECTED
CODEPAGE   NAME=config     START=0x300000          END=0x30000D       PROTECTED
CODEPAGE   NAME=devid      START=0x3FFFFE          END=0x3FFFFF       PROTECTED
CODEPAGE   NAME=eedata     START=0xF00000          END=0xF003FF       PROTECTED

#IFDEF _EXTENDEDMODE
  DATABANK   NAME=gpre       START=0x0               END=0x5F
#ELSE
  ACCESSBANK NAME=accessram  START=0x0               END=0x5F
#FI

DATABANK   NAME=gpr0       START=0x60              END=0xFF
DATABANK   NAME=gpr1       START=0x100             END=0x1FF
DATABANK   NAME=gpr2       START=0x200             END=0x2FF
DATABANK   NAME=gpr3       START=0x300             END=0x3FF
DATABANK   NAME=gpr4       START=0x400             END=0x4FF

DATABANK   NAME=NokiaBank     START=0x500               END=0x6FF
// DATABANK   NAME=gpr5       START=0x500             END=0x5FF
// DATABANK   NAME=gpr6       START=0x600             END=0x6FF
SECTION NAME=NokiaBank   RAM=NokiaBank

DATABANK   NAME=GrosseBank      START=0x700               END=0x9FF
// DATABANK   NAME=gpr7       START=0x700             END=0x7FF
// DATABANK   NAME=gpr8       START=0x800             END=0x8FF
// DATABANK   NAME=gpr9       START=0x900             END=0x9FF

SECTION NAME=GrosseBank RAM=GrosseBank


DATABANK   NAME=gprA       START=0xA00             END=0xAFF
DATABANK   NAME=gprB       START=0xB00             END=0xBFF
DATABANK   NAME=gprC       START=0xC00             END=0xCFF
DATABANK   NAME=gprD       START=0xD00             END=0xDFF

#IFDEF _DEBUGDATASTART
  DATABANK   NAME=gprE       START=0xE00             END=_DATAEND
  DATABANK   NAME=dbgspr     START=_DEBUGDATASTART   END=_DEND           PROTECTED
#ELSE //no debug
  DATABANK   NAME=gprE       START=0xE00             END=0xEFF
#FI

DATABANK   NAME=gprF       START=0xF00             END=0xF37
DATABANK   NAME=sfr15      START=0xF38             END=0xF5F          PROTECTED
ACCESSBANK NAME=accesssfr  START=0xF60             END=0xFFF          PROTECTED

#IFDEF _CRUNTIME
  SECTION    NAME=CONFIG     ROM=config
  #IFDEF _DEBUGDATASTART
    STACK SIZE=0x100 RAM=gprD
  #ELSE
    STACK SIZE=0x100 RAM=gprE
  #FI
#FI

and other buffer for communications
in GrosseBank area of 512 bytes (2 banks)

Code: 
#define MAX_LEN1 128
#define MAX_LEN2 128
#define MAX_LEN3 128
#define MAX_LEN4 120   

#pragma udata GrossBank
static unsigned char buffer[MAX_LEN1];
static unsigned char EdfInfo[MAX_LEN2];
static unsigned char Texte[MAX_LEN3];
static unsigned char BT[MAX_LEN4];
#pragma
 


Thanks for the example. I notice you modified the memory to put "DATABANK NAME=NokiaBank START=0x500 END=0x6FF" and "DATABANK NAME=GrosseBank START=0x700 END=0x9FF". Did you try put 'PROTECTED' onto it?

For me, if I don't put 'PROTECTED', my firmware can be compile successfully. But I notice that my compiler will assign some other variable to the location I fixed. I know this can be fixed by putting the word 'PROTECTED' beside it.
But when I put 'PROTECTED', the compiler compile failed with the 'cannot fit error'. Why? Does this means that my memory is used up all?
Is it that I can fixed anywhere from grp1 to grp7? How do we know where the compiler assigned the other variables?
 
Last edited:

hello,




you want to use 1536-256= 1280 bytes for your own usage !
i think the compiler doesn't have egnough RAM area for itself !
and i think it's better to allocate modulo BANK of 256 bytes, and not cut somwhere in a BANK.
ex:
DATABANK NAME=large_udata START=0x100 END=0x4FF // 1023 bytes
DATABANK NAME=gpr5 START=0x500 END=0x5FF


what table size do you need ?
one of 650 and another one of 400 bytes ?
at the same time ?

Maybe your PIC is not appropriate for your application.
Not egnouh RAM
do you need USB ?
because PIC18F26K22 maybe can replace 25K20.

Here is my tests with PROTECTED

if i put PROTECTED ike this
DATABANK NAME=NokiaBank START=0x500 END=0x6FF PROTECTED
DATABANK NAME=GrosseBank START=0x700 END=0x9FF
Click to expand...

i get this error
MPLINK 4.45, Linker
Device Database Version 1.10
Copyright (c) 1998-2011 Microchip Technology Inc.
Error - section 'GrossBank' can not fit the section. Section 'GrossBank' length=0x000001f8
Errors : 1

after , if i put PROTECTED like this
DATABANK NAME=NokiaBank START=0x500 END=0x6FF
DATABANK NAME=GrosseBank START=0x700 END=0x9FF PROTECTED
Click to expand...

i get this error
MPLINK 4.45, Linker
Device Database Version 1.10
Copyright (c) 1998-2011 Microchip Technology Inc.
Error - section '.idata_18F46K22_EDFinfo_Nokia_BT_Archos_131127_20Mhz.o'
can not fit the section. Section .idata_18F46K22_EDFinfo_Nokia_BT_Archos_131127_20Mhz.o'
length=0x00000288
Errors : 1


Without PROTECTED, no problemo..
MPLINK 4.45, Linker
Device Database Version 1.10
Copyright (c) 1998-2011 Microchip Technology Inc.
Errors : 0

MP2HEX 4.45, COFF to HEX File Converter
Copyright (c) 1998-2011 Microchip Technology Inc.
Errors : 0

remember, in my case i have 3.5K of RAM!!!


I think PROTECTED is for compiler protection.
To avoid user program to corrupt SFR Area or DEBUG area

Other advise ?
 

Let me give another example. Below is my code:

Code: 
ACCESSBANK NAME=accessram  START=0x0            END=0x5F
DATABANK   NAME=gpr0       START=0x60           END=0xFF
DATABANK   NAME=gpr1       START=0x100          END=0x1FF
DATABANK   NAME=gpr2       START=0x200          END=0x2FF
DATABANK   NAME=gpr3       START=0x300          END=0x3FF
DATABANK   NAME=gpr4       START=0x400          END=0x4FF	
DATABANK   NAME=gpr5       START=0x500          END=0x5FF
DATABANK   NAME=udata1      START=0x600          END=0x7FF			
//DATABANK   NAME=gpr7       START=0x700          END=0x7FF

DATABANK   NAME=sfr15      START=0xF53             END=0xF5F          PROTECTED
ACCESSBANK NAME=accesssfr  START=0xF60          END=0xFFF

I put my udata1 bigger memory so that can support 511 buffer.
And in the main.c file I have this:

Code: 
#pragma udata udata1
static 	BYTE 	RS485RXDATA[511];

So, if I put the word 'PROTECTED' after the line 'DATABANK NAME=udata1 START=0x600 END=0x7FF', it still come out error saying ' Error - section 'udata1' can not fit the section. Section 'udata1' length=0x000001ff'.
I have to make RS485RXDATA[256] only can compile successful. Why?
 

hello,

do you have aterminateur for #pragma ?
like this
Code: 
#pragma udata udata1
static 	BYTE 	RS485RXDATA[511];
[COLOR="#FF0000"][B]#pragma[/B][/COLOR]

I am working on another subject "Petite Fat for SD card"
and also use a buffer of 512 bytes
same as your case...
and add PROTECTED , no error in compiling results..

BUT MY APPLICATION DOESN'T USE A LOT OF RAM for other variable..
and this PIC has 3896 bytes of RAM !
Are you also using a debugger ? wich can use some RAM area.
Maybe your compiler need some amount of RAM , wich can overlap your reservation.


Code: 
/ rev PF 8_12_2013 pour SD card 
// File: 18f26k22_g.lkr
// Generic linker script for the PIC18F26K22 processor

#DEFINE _CODEEND _DEBUGCODESTART - 1
#DEFINE _CEND _CODEEND + _DEBUGCODELEN
#DEFINE _DATAEND _DEBUGDATASTART - 1
#DEFINE _DEND _DATAEND + _DEBUGDATALEN

LIBPATH .

#IFDEF _CRUNTIME
  #IFDEF _EXTENDEDMODE
    FILES c018i_e.o
    FILES clib_e.lib
    FILES p18f26k22_e.lib

  #ELSE
    FILES c018i.o
    FILES clib.lib
    FILES p18f26k22.lib
  #FI

#FI

#IFDEF _DEBUGCODESTART
  CODEPAGE   NAME=page       START=0x0               END=_CODEEND
  CODEPAGE   NAME=debug      START=_DEBUGCODESTART   END=_CEND        PROTECTED
#ELSE
  CODEPAGE   NAME=page       START=0x0               END=0xFFFF
#FI

CODEPAGE   NAME=idlocs     START=0x200000          END=0x200007       PROTECTED
CODEPAGE   NAME=config     START=0x300000          END=0x30000D       PROTECTED
CODEPAGE   NAME=devid      START=0x3FFFFE          END=0x3FFFFF       PROTECTED
CODEPAGE   NAME=eedata     START=0xF00000          END=0xF003FF       PROTECTED

#IFDEF _EXTENDEDMODE
  DATABANK   NAME=gpre       START=0x0               END=0x5F
#ELSE
  ACCESSBANK NAME=accessram  START=0x0               END=0x5F
#FI

DATABANK   NAME=gpr0       START=0x60              END=0xFF
DATABANK   NAME=gpr1       START=0x100             END=0x1FF
DATABANK   NAME=gpr2       START=0x200             END=0x2FF
DATABANK   NAME=gpr3       START=0x300             END=0x3FF
DATABANK   NAME=gpr4       START=0x400             END=0x4FF
DATABANK   NAME=gpr5       START=0x500             END=0x5FF
DATABANK   NAME=gr6        START=0x600			   END=0x6FF
//DATABANK   NAME=gpr7       START=0x700             END=0x7FF
//DATABANK   NAME=gpr8       START=0x800             END=0x8FF
//DATABANK   NAME=gpr9       START=0x900             END=0x9FF

DATABANK   NAME=BigBuffer    START=0x700             END=0x9FF  PROTECTED
    
DATABANK   NAME=gprA       START=0xA00             END=0xAFF   
DATABANK   NAME=gprB       START=0xB00             END=0xBFF
DATABANK   NAME=gprC       START=0xC00             END=0xCFF
DATABANK   NAME=gprD       START=0xD00             END=0xDFF

#IFDEF _DEBUGDATASTART
  DATABANK   NAME=gprE       START=0xE00             END=_DATAEND
  DATABANK   NAME=dbgspr     START=_DEBUGDATASTART   END=_DEND           PROTECTED
#ELSE //no debug
  DATABANK   NAME=gprE       START=0xE00             END=0xEFF
#FI

DATABANK   NAME=gprF       START=0xF00             END=0xF37
DATABANK   NAME=sfr15      START=0xF38             END=0xF5F          PROTECTED
ACCESSBANK NAME=accesssfr  START=0xF60             END=0xFFF          PROTECTED

SECTION    NAME=BigBuffer RAM=BigBuffer


#IFDEF _CRUNTIME
  SECTION    NAME=CONFIG     ROM=config
  #IFDEF _DEBUGDATASTART
    STACK SIZE=0x100 RAM=gprD
  #ELSE
    STACK SIZE=0x100 RAM=gprE
  #FI
#FI
 

Yes. I did put the #pragma after the #pragma udata udata1.
Yes. I'm compiling while debugging. Are you sure the debugger has used the RAM. That means if I do not use the debugger, it will successfully be compiled when I use RS485RXDATA[511]. I'll try it first.

- - - Updated - - -

Nope. Still fail with the same error message when I compile without debugger.

- - - Updated - - -

Now does that means I really have not enough RAM already if I use RS485RXDATA[511]?
How do we check what is the amount of RAM used currently?
 

hello,


Have a look on "memory usage gauge "
it is not very accurate ,but will show if you have some space of ram available..

The best way to check in details :
project
build options
project
Mplink linker
coche Generate map file

Build all again
and open your *.map file
and check inside all RAM allocations..
 

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