Experimental study on SDRAM

[email protected]:~/my03$ lltotal 12-rw-rw-r-- 1 chunli chunli 2703  Apr 13 03:49 head. s-rw-rw-r-- 1 chunli chunli  532 apr 13 03:50 leds.c-rw-rw-r--  1 chunli chunli  312 apr 13 03:50 makefile[email protected] : ~/my03$ cat head. s  @*************************************************************************@ file:head.s@   Function: Set SDRAM, copy the program to SDRAM, then skip to SDRAM to continue execution @*******************************************************************        .equ        mem_ctl_ base,       0x48000000.equ         Sdram_base,         0x30000000.text.global _start_start:     bl  disable_watch_dog               @  turn off watchdog, otherwise the CPU will continue to restart      bl  memsetup                         @  set up storage controllers      bl  copy_steppingstone_to_sdram     @  copy code to SDRAM      ldr pc, =on_sdram                    @  jump into SDRAM to continue execution of ON_SDRAM:&NBSP;&NBSP;&NBSP;&NBSP;LDR&NBSP;SP,  =0x34000000                  @  Set up Stacks     bl  mainhalt_loop:    b    halt_loopdisable_watch_dog:    @  Write 0 to watchdog Register      Mov r1,      #0x53000000     mov r2,      #0x0      str r2,     [r1]    mov pc,      lr      @  Back to copy_steppingstone_to_sdram:     @  Copy all Steppingstone 4K data to SDRAM     @ steppingstone start address is 0x00000000, SDRAM start address is 0x30000000        mov r1,  #0      ldr r2, =SDRAM_BASE    mov r3,  #4 *10241:     &NBSP;&NBSP;LDR&NBSP;R4,&NBSP;[R1], #4      @  read 4 bytes of data from Steppingstone and let the source address add 4  &NBSP;&NBSP;&NBSP;STR&NBSP;R4,&NBSP;[R2], #4      @  copy this 4-byte data into the SDRAM and let the address of the target add 4     cmp r1, r3          @   Decide whether to complete: the source address is equal to Steppingstone's address?     bne 1b               @  if not finished, continue     mov pc,     lr       @  return memsetup:    @  set up the storage controller to use peripherals such as SDRAM      mov r1,      #MEM_CTL_BASE        @  Start address of the 13 registers of the storage controller     adrl    r2, mem_cfg_val          @  The starting storage address for these 13 values     add r3,      r1,  #52              @  13*4 = 541:      ldr r4,     [r2],  #4             @  Read the set value and let R2 add 4     str r4,     [r1],  #4              @  write this value to the register and let R1 add 4    cmp r1,     r3                   @  Determine if all 13 registers are set     bne 1b                           @  if not written, Continue     mov pc,     lr                   @  return. Align 4mem_cfg_val:     @  Storage Controller 13 register setting values     .long   0x22011110       @ BWSCON    .long   0x00000700       @ bankcon0    .long   0x00000700      @  bankcon1    .long   0x00000700      @  bankcon2    .long   0x00000700      @  bankcon3      .long   0x00000700       @ BANKCON4    .long   0x00000700       @ BANKCON5    .long   0x00018005       @ BANKCON6    .long   0x00018005       @ BANKCON7    .long   0x008C07A3       @ REFRESH    .long   0x000000B1       @ banksize    .long   0x00000030      @ mrsrb6     .long   0x00000030      @ MRSRB7[email  protected]:~/my03$ [email protected]:~/my03$ [email protected]:~/my03$ [email  protected]:~/my03$ [email protected]:~/my03$ [email protected]:~/my03$ [email  protected]:~/my03$ [email protected]:~/my03$ cat leds.c  #defineGPFCON (* (volatile  unsigned long *) (0x56000050) #defineGPFDAT (* (volatile unsigned long *) 0x56000054) #defineGPF4_out (1<< (4*2)) #defineGPF5_out (1<< (5*2)) #defineGPF6_out (1<< (6*2)) void   Wait (volatile unsigned long dly) {for (;  dly > 0; dly--);} Int main (void) {unsigned long i = 0; Gpfcon = gpf4_out| Gpf5_out| gpf6_out;//  set led1,2,4 corresponding GPF4/5/6 three pins to output while (1) {WAIT (30000); gpfdat =  (~ (i<<4)); //  light led1,2,4if (++i == 8) i = 0 according to the value of I;} return 0;} [email protected]:~/my03$ [email protected]:~/my03$ [email protected]:~/my03$ [ Email protected]:~/my03$ [email protected]:~/my03$ [email protected]:~/my03$ cat  makefile sdram.bin : head. S  leds.carm-linux-gcc  -c -o head.o head. sarm-linux-gcc -c -o leds.o leds.carm-linux-ld -ttext 0x30000000 head.o  leds.o -o sdram_elfarm-linux-objcopy -O binary -S sdram_elf  Sdram.binarm-linux-objdump -d -m arm  sdram_elf > sdram.disclean:rm  -f   sdram.dis sdram.bin sdram_elf *.o[email protected]:~/my0

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Experimental study on SDRAM