rom.s

启动代码

@On-chip ROM size if 8KB, On-chip RAM is 16KB.

@internal RAM allocate:
@	bios: 0x40003000~0x40003fff
@	user: 0x40000000~0x40003ffc


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.global _start
_start:
	b 		ResetHandler
password:	
	.ascii   "ANYKA323"
flash_information:
	.byte	4               		@ page size = 2KB
	.byte	6						@ read page number
	.byte	2               		@ command cycle number
	.byte	2               		@ cycle number of offset address in page
	.byte	3           			@ cycle number of page address
	.byte	0x00        			@ unlock command value for read page
	.byte	0x30        			@ confirm command value for read page(if need)
	.byte   0						@ reversed, only for align
	.word   0x000c3671      		@ FLASH command timing parameter
	.word   0x000d3637      		@ FLASH data timing parameter
	.hword  0           			@ reset wait time 2mSecond. 0: use default value; other: new wait value;
	.hword  0           			@ read page command wait time 1mSecond. 0: use default value; other: new wait value;
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	.align 4	@代码起始地址对齐32bit
	
	.word   0x1580f1ec              @chip id
	.hword  2048                    @page size
	.hword  64                      @page of one blok
	.hword  1024                    @total block number
	.hword  1024                    @if size is 512M, A29 must the same when copy back, we thougt the A29=0 is a group,A29=1 is another group   
	.hword  1024                    
	.byte   64                      @spare size
	.byte   2                       @column address cycle
	.byte   0x0f                    @last column  addrress cycle mask bit
	.byte   2                       @row address cycle
	.byte   0xff                    @last row address cycle mask bit
	.byte   0x0                     @if is a custom nandflash(ohter not typicly nandflash),set bit,use this would fast
	
	.align 4	@代码起始地址对齐32bit

ResetHandler:
	@enable all clock
	ldr     r1,=0xffffffff
	ldr     r0,=0x20000000
	str     r1,[r0]
	
  @set power off pin high. if the power off pin is low, the machine can not run on.
    ldr r0, =0x20090000
    ldr r1, =0x0400
    str r1, [r0]
    ldr r0, =0x20090010
    @ldr r1, =0x0400
    ldr r1, =0xffffffff
    str r1, [r0]
    
  @dislable all interrupt
	ldr	r0,=0x20000018
	ldr	r1,=0xffff
	str	r1, [r0]
	ldr	r0,=0x2000001c
	str	r1, [r0]
	
	@set moregpio3(bit27)=0, maddr[24:17] as bus address
	ldr r0, =0x20090020
	ldr r1, [r0]
	bic r1, r1, #0x08000000
	str r1,[r0]
	@set bit1/pull1_reg[1]=1, close mdata[15:0] pull up
	ldr r0, =0x20090060
	ldr r1, [r0]
	orr r1, r1, #0x00000002
	str r1,[r0]		
	
	@set up sdram which value is best?????
	ldr 	r0, =0x200b0000
	ldr 	r1, =0x100f400
	str 	r1, [r0]
	
	@set up sram
	@ldr 	r0, =0x200b0000
	@ldr 	r1, =0x000f0000
	@str 	r1, [r0]
	
	@set up ssram
	@ldr 	r0, =0x200b0000
	@ldr 	r1, =0x00020000
	@str 	r1, [r0]

@**************************************
	ldr	r0,=0x13
	msr	cpsr, R0
	ldr	r1,=0x30300000
	MOV	SP, R1   		
	ldr	pc, =boot_main
@**************************************