ARM编程中Flash ROM驱动示例

Intel Flash芯片 i28f160,i28f320:

i28F320B: 64*64K,64个blocks,4M空间,每个block 64K,第一个64K由8个8*8K小blocks组成.

每个Black可以被独立擦写(寿命周期) 100,000次以上

Flash操作的大概步骤:

flash读写操作中,读应该很简单,和RAM一样,写就复杂一点.
Intel TE28F320C3的flash是4M空间
flash空间,划分成许多的block,Intel TE28F320C3的flash是4M空间,64个block,每个block由64K.
要对所有的block单独进行操作, 每个操作结束,都需要判断状态,
每个block操作的大概步骤如下:
1.unlock
2.erase
3.check empty
所有的block完成上述操作,且状态正确,才能进行下一步,写
4.write

ARM汇编程序

LDR r2, =FlashBase ;Flash起始地址

//第一步,UNLOCK的64个block,步骤和上边一样


MOV r1,#63 ;63x64k block 计数


01 LDRB r3, =X16_FLASH_COMMAND_CONFIG_SETUP

STRB r3, [r2] ;该block的首地址

LDRB r3, =X16_FLASH_COMMAND_UNLOCK_BLOCK

STRB r3, [r2] ;将Unlock命令写入

ADD r2, r2, #0x10000 ;64K
SUBS r1, r1, #1
BNE %b01
;Unlock OK ;Unlock 完成


//第二布,擦除blocks

LDR r0, =FlashBase
LDR r1,=63 ;擦除 63x64k block
01 LDR r3, =X16_FLASH_COMMAND_ERASE
LDR r2, =X16_FLASH_COMMAND_CONFIRM
ORR r3, r3, r2, LSL #16
STR r3, [r0]
LDR r3, =X16_FLASH_COMMAND_STATUS ;检查寄存器状态
STRB r3, [r0]
02 LDRB r3, [r0] ;读状态
TST r3, #X16_FLASH_STATUS_READY
BEQ %b02 ;若状态ready,执行下一个
TST r3, #X16_FLASH_STATUS_ERROR
BNE error_erase_block
ADD r0, r0, #0x10000
SUBS r1, r1, #1
BNE %b01
B EraseOK
error_erase_block
..............
;EraseOK ;擦除完成

//第三步,检查flash是否为空

;Check Flash Empty
LDR r4, =FlashBase
LDR r5, =0x100000 ;检查 1MB
LDR r0, =0xffffffff
loop_1
LDR r1, [r4]
CMP r1, r0 ;比较地址内容和0xffffffff
BNE empty_error
ADD r4, r4, #4
CMP r4, r5
BLO loop_1
B CheckOK
empty_error
.................
CheckOK
.................

;Check empty OK ;检查完成

//第四步,写flash

;Burn data to Flash ROM

LDR r6, =Length_Flash ;定义数据长度
LDR r0, =FlashBase
LDR r1, =BufferBase
MOV r9, #0
LDR r4,=0x10000000
LDR r7,=0xc0001000
STR r4, [r7]
LDR r1, [r1, r9]

03 LDR r3, =X16_FLASH_COMMAND_WRITE
STRB r3, [r0] ;把写命令放入Block首地址
LDR r3, =X16_FLASH_COMMAND_STATUS
LDR r2, [r7]
LDR r5, =0x0000ffff
AND r2, r2, r5
ORR r2, r2, r3, LSL #16
STR r2, [r0]
02 LDR r3, [r0] ;读状态寄存器状态
TST r3, #X16_FLASH_STATUS_READY
BEQ %b02 ;若状态ready,执行下一个

LDR r3, =X16_FLASH_COMMAND_WRITE
LDR r2, [r7]
LDR r5, =0xffff0000 ;
AND r2, r2, r5
ORR r3, r3, r2
STR r3, [r0]

LDR r3, =X16_FLASH_COMMAND_STATUS
STRB r3, [r0]
02 LDR r3, [r0] ; read status
TST r3, #X16_FLASH_STATUS_READY
BEQ %b02

LDR r4, =X16_FLASH_COMMAND_READ
STRB r4, [r0]
ADD r0, r0, #4
LDR r8, [r7]
ADD r8, r8,#1
STR r8, [r7]
ADD r8, r8, #4
writenext

SUBS r6, r6, #4 ;if no finished goto 03
BHI %b03
TST r3, #X16_FLASH_STATUS_ERROR
BNE error_write
LDR r3, =X16_FLASH_COMMAND_READ
STRB r3, [r0]
B BurnOK
error_write
..........
BurnOK

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