Samsung 2440 ARM initialization

1. Use the initialization file that Samsung has already written

1. Create a project folder first
2. Create a project and save it in the new folder
3. Drag the INC and SRC folders in the INIT folder written by ARM Samsung into the new folder.
4. Create a C file, such as LCD1602.c, and write a void xmain() function or a void xxxx() function
5. Add 2440init in SRC to the project.
6. Change the corresponding main function entry in 2440init to the function xmain in LCD1602.c. This is very important so that other functions can be written by adding header files, otherwise they cannot be executed. See the figure below 






2. Write your own initialization
1. Create a project folder first
2. Create a project and save it in the new folder (the path is in English)
3. Create your own initialization function init.s. The initialization file must be written in assembly language. At least the following code is required (this is very important)
                    MPORT name AREA Init,CODE,READONLY
                    ENTRY  
                    bl name
                    end
   Note: name must be the main function name, other functions can be written according to the general writing method of C files, such as the following program code:
#include"2440addr.h" //Defines the address and name of each special function register. This header file must be called to use it./*===
If this header file is not called, the definition name and address statement to be used must be declared before the main program.
#define rGPBCON (*(volatile unsigned *)0x56000010)//Port B control
#define rGPBDAT (*(volatile unsigned *)0x56000014)//Port B data
#define rGPBUP (*(volatile unsigned *)0x56000018)//Pull-up control */    
/* Custom simple delay program */ 
int name(int times)
{
    int i;
    for(i=0;i    return 0;
}

/* Main program */
void xmain(void) //The main function name corresponds to the main function entry address and is defined in 2440init.s
{ //Do not write main or Main at will, check the 2440init.s file (see the figure below)


        rGPBCON |=0x3fc00; //GPB5-8 able output, first let 11 1111 11xx xxxx xxxx
        rGPBCON &=0x157ff; // 00-in 01-out 01 0101 01xx xxxx xxxx
                                         // P8 P6P7 P5P4 P3P2 P1P0
                                               // G GG G x xx xx
while(1)
    {

             rGPBDAT|=0x1e0;//GPB8 output 0 1 111x xxxx
             rGPBDAT&=0xeff;// 0 111x xxxx
             delay(5);//Call the delay program written in assembly language 

             rGPBDAT|=0x1e0;//GPB7 output 0 1 111x xxxx
             rGPBDAT&=0xf7f;// 1 011x xxxx
             delay(5);//Call the delay program written in assembly language 


             rGPBDAT|=0x1e0;//GPB6 output 0 1 111x xxxx
             rGPBDAT&=0xfbf;// 1 101x xxxx      
             delay(5);//Call the delay program written in assembly language 

             rGPBDAT|=0x1e0;//GPB5 output 0 1 111x xxxx
             rGPBDAT&=0xfdf;// 1 110x xxxx       
             delay(5);//Call the delay program written in assembly language 


    }
}

You can also continue to follow the steps below to add
4. Use the header file method to write the sub-functions you need in the form of header files.h. Write as many sub-functions as you need.
5. Write your own main function. The name of the main function should be the same as the name in the initialization function.
6. Add the above files to the project.