declaring 512 byte array for PIC

[redsuns]

hi

i need to declare a 512 byte array for my code because i need to get those data from a camera and send it to a FAT16 SD card

when i was going through the code, it gives me no definition that matches the type of section "udata_filename_0" when i was compiling it

it works fine if the total array declare is less than 256 byte
i opened the .asm file and the udata use percentage is not half yet
so how can i define a 512 byte array?
i just write a simple code to test how to declare this array but fail
i try to compile this code with 2 different compiler MPLAB IDE with MPLAB C18 and sdcc

the error msg is like this for sdcc
warning:relocation of section "udata_a_1"fail,relocating to a shared memory location
error:linker script has no definition that matches the type of section "udata_a_1"

and MPLAB C18 gives
Error - section '.udata_a.o' can not fit the section. Section '.udata_a.o' length=0x00000206

//file include
#include <p18f2620.h>
#include <stdio.h>
//***************************

//***********define************
#define TX PORTCbits.RC6
#define RX PORTCbits.RC7
//*****************************

//*****global variable**********
unsigned char rx_buffer[6];
unsigned char tx_buffer[512];
//******************************

//start coding
void main()
{
//register mapping for asynchronous transmit
TRISCbits.TRISC0 = 1; //setting pin as RX pin
INTCON |= 0xC0; //enable interrupts
RCSTAbits.SPEN = 1; //enable SPEN
TXSTAbits.SYNC = 0; //clear SYNC bits for asynchronous mode
TXSTAbits.BRGH = 1;//clock configure
PIE1 = 0x38;//set interrupt for EUSART & SPI
TXSTAbits.TXEN = 1; //transmit enable , trigger TXIF
RCSTAbits.CREN = 1; // enables receiver
SPBRG = 21; //57.6K baud rate
//end
}

 

[Pommie]

You need to copy the linker script into your project folder and change it to,

// File: 18f2620.lkr
// Sample linker script for the PIC18F2620 processor

LIBPATH .

FILES c018i.o
FILES clib.lib
FILES p18f2620.lib

CODEPAGE   NAME=page       START=0x0               END=0xFFFF
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

ACCESSBANK NAME=accessram  START=0x0            END=0x7F
DATABANK   NAME=gpr0       START=0x80           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=gpr6       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=gpr10      START=0xA00          END=0xAFF
DATABANK   NAME=gpr11      START=0xB00          END=0xBFF
[COLOR="red"]//DATABANK   NAME=gpr12      START=0xC00          END=0xCFF
//DATABANK   NAME=gpr13      START=0xD00          END=0xDFF
DATABANK   NAME=bigarray   START=0xC00          END=0xDFF[/COLOR]
DATABANK   NAME=gpr14      START=0xE00          END=0xEFF
DATABANK   NAME=gpr15      START=0xF00          END=0xF7F
ACCESSBANK NAME=accesssfr  START=0xF80          END=0xFFF          PROTECTED

SECTION    NAME=CONFIG     ROM=config

STACK SIZE=0x100 RAM=gpr14

And then change your program to,

//file include
#include <p18f2620.h>
#include <stdio.h>
//***************************

//***********define************
#define TX PORTCbits.RC6 
#define RX PORTCbits.RC7
//*****************************

//*****global variable**********
[COLOR="red"]#pragma udata
unsigned char rx_buffer[6];
#pragma udata bigarray
unsigned char tx_buffer[512];[/COLOR]
//******************************
#pragma code

//start coding
void main()
{
    //register mapping for asynchronous transmit
    TRISCbits.TRISC0 = 1; //setting pin as RX pin
    INTCON |= 0xC0; //enable interrupts
    RCSTAbits.SPEN = 1; //enable SPEN
    TXSTAbits.SYNC = 0; //clear SYNC bits for asynchronous mode
    TXSTAbits.BRGH = 1;//clock configure
    PIE1 = 0x38;//set interrupt for EUSART & SPI
    TXSTAbits.TXEN = 1; //transmit enable , trigger TXIF
    RCSTAbits.CREN = 1; // enables receiver
    SPBRG = 21; //57.6K baud rate
//end
}

Make sure your project is using the modified linker script and all should work.

I chose banks 12 and 13 as bank 14 is used for the stack.

Mike.

 

[redsuns]

it really does work , thank you
if i need 2 512 array then i can combine 2 more stack together with another name and pragma that name to use it is it?

 

[Pommie]

Or just combine 4 banks. I suggest 10, 11, 12 & 13.

Mike.