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修改FLASH数据通常需要很长时间，不像RAM那样可以实时操作。而且擦除、编程或读取FLASH数据需要遵循相当复杂的时序步骤。N76E003提供方便FALSH编程方式，可以帮助用户通过IAP方式，重新编程FLASH内容。IAP就是通过软件实现在线电擦除和编程的方法。
通过设置IAPEN（CHPCON.0受TA保护）使能IAP，并且设置IAPUEN寄存器的相应位，使能需要升级的FLASH区域（CONFIG、LDROM、APROM），用户将16位操作地址写入IAPAH和IAPAL，数据写入IAPFD，命令写入IAPCN。然后通过设置触发位IAPGO(IAPTRG.0)，去执行IAP。注意：IAPTRG也受TA保护。此时，CPU保持程序计数器，内嵌IAP自动控制内部充电泵提高电压和信号时序。擦除和编程时间是内部控制的，与工作电压和频率无关。通常页擦除时间是5ms，字节编程时间是 3.5μs。IAP动作完成后，程序计数器继续运行之后的指令，IAPGO位将自动清零。IAPFF (CHPCON.6)是IAP错误标志，可以用来检查之前IAP操作成功与否。通过这些纯软件的设置，用户可以很方便对FLASH存储器进行擦除、编程和校验。
IAP可以方便用户更新FLASH内容，不过用户必须遵循一定规则，以确保IAP正确执行，否则可能引起不确定的结果，甚至损坏器件。此外，下文对于正确执行IAP有很好建议。
(1)没有IAP操作时，用户必须清IAPEN (CHPCON.0)位。可以防止系统意外触发IAP。此外，IAP需要使用内部HIRC振荡器。如果选择外部时钟源，禁止IAP将停止内部HIRC，可以达到省电的目的。注：写IAPEN受TA保护。
(2)当LOCK位(CONFIG0.1) 被激活，IAP读、写或擦除仍然有效。
在进行IAP时，如果中断打开应该临时清除EA位
擦除或编程的页不能是当前代码执行的页。否则会出现不可预计程序动作，甚至破坏存储的数据
使用flash存储器作为数据存储
在一般应用中，有时需要一些数据在断电情况下不能丢失，以便用户读回或更新，作为系统控制的参数。N76E003支持IAP功能并且存储在flash中的字节都可以用MOVC指令读取，所以很适合作为非易失数据存储器。Flash写次数为100,000次，以下参考应用代码： 汇编例程如下:
;******************************************************************************
; This code illustrates how to use IAP to make APROM 201h as a byte of
; Data Flash when user code is executed in APROM.
;******************************************************************************
PAGE_ERASE_AP EQU 00100010b
BYTE_PROGRAM_AP EQU 00100001b
ORG 0000h
MOV TA,#0Aah ;CHPCON is TA protected
MOV TA,#55h
ORL CHPCON,#00000001b ;IAPEN = 1, enable IAP mode
MOV TA,#0Aah ;IAPUEN is TA protected
MOV TA,#55h
ORL IAPUEN,#00000001b ;APUEN = 1, enable APROM update
MOV IAPCN,#PAGE_ERASE_AP ;Erase page 200h~27Fh
MOV IAPAH,#02h
MOV IAPAL,#00h
MOV IAPFD,#0FFh
MOV TA,#0Aah ;IAPTRG is TA protected
MOV TA,#55h
ORL IAPTRG,#00000001b ;write ‘1’ to IAPGO to trigger IAP process
MOV IAPCN,#BYTE_PROGRAM_AP ;Program 201h with 55h
MOV IAPAH,#02h
MOV IAPAL,#01h
MOV IAPFD,#55h MOV TA,#0Aah
MOV TA,#55h
ORL IAPTRG,#00000001b
MOV TA,#0Aah
MOV TA,#55h
ANL IAPUEN,#11111110b ;APUEN = 0, disable APROM update
MOV TA,#0Aah
MOV TA,#55h
ANL CHPCON,#11111110b ;IAPEN = 0, disable IAP mode
MOV DPTR,#201h
CLR A
MOVC A,@A+DPTR ;Read content of address 201h
MOV P0,A
SJMP $ C 语言例程如下:
//******************************************************************************
// This code illustrates how to use IAP to make APROM 201h as a byte of
// Data Flash when user code is executed in APROM.
//******************************************************************************
#define PAGE_ERASE_AP 0x22
#define BYTE_PROGRAM_AP 0x21
/*Data Flash, as part of APROM, is read by MOVC. Data Flash can be defined as
128-element array in “code” area from absolute address 0x0200 */
volatile unsigned char code Data_Flash[128] _at_ 0x0200;
Main (void)
{
TA = 0xAA; //CHPCON is TA protected
TA = 0x55;
CHPCON |= 0x01; //IAPEN = 1, enable IAP mode
TA = 0xAA; //IAPUEN is TA protected
TA = 0x55;
IAPUEN |= 0x01; //APUEN = 1, enable APROM update
IAPCN = PAGE_ERASE_AP; //Erase page 200h~27Fh
IAPAH = 0x02;
IAPAL = 0x00;
IAPFD = 0xFF;
TA = 0xAA; //IAPTRG is TA protected
TA = 0x55;
IAPTRG |= 0x01; //write ‘1’ to IAPGO to trigger IAP process
IAPCN = BYTE_PROGRAM_AP; // Program 201h with 55h
IAPAH = 0x02;
IAPAL = 0x01; IAPFD = 0x55; TA = 0xAA;
TA = 0x55;
IAPTRG |= 0x01; //write ‘1’ to IAPGO to trigger IAP process
TA = 0xAA; //IAPUEN is TA protected
TA = 0x55;
IAPUEN &= ~0x01; //APUEN = 0, disable APROM update
TA = 0xAA; //CHPCON is TA protected
TA = 0x55;
CHPCON &= ~0x01; //IAPEN = 0, disable IAP mode
P0 = Data_Flash[1]; //Read content of address 200h+1
while(1);
} N76E003 APROM程序DATAFLASH为EEPROM方式 
#include <stdio.h>#include "N76E003.h"#include "Common.h"#include "Delay.h"#include "SFR_Macro.h"#include "Function_Define.h"bit BIT_TMP;//-------------------------------------------------------------------------UINT8 read_APROM_BYTE(UINT16 code *u16_addr){ UINT8 rdata; rdata = *u16_addr>>8; return rdata;}//-------------------------------------------------------------------------/*****************************************************************************************************************write_DATAFLASH_BYTE :user can copy all this subroutine into project, then call this function in main.******************************************************************************************************************/ void write_DATAFLASH_BYTE(UINT16 u16_addr,UINT8 u8_data){ UINT8 looptmp=0,u8_addrl_r; unsigned char code *cd_longaddr; unsigned char xdata *xd_tmp; //Check page start address u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { u8_addrl_r = 0; } else { u8_addrl_r = 0x80; }//Save APROM data to XRAM xd_tmp = 0x80; cd_longaddr = (u16_addr&0xff00)+u8_addrl_r; while (xd_tmp !=0x100) { *xd_tmp = *cd_longaddr; looptmp++; xd_tmp++; cd_longaddr++; }// Modify customer data in XRAM u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { xd_tmp = u8_addrl_r+0x80; } else { xd_tmp = u8_addrl_r+0; } *xd_tmp = u8_data;//Erase APROM DATAFLASH page IAPAL = u16_addr; IAPAH = u16_addr>>8; IAPFD = 0xFF; set_IAPEN; set_APUEN; IAPCN = 0x22; set_IAPGO; //Save changed RAM data to APROM DATAFLASH u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { u8_addrl_r =0; } else { u8_addrl_r = 0x80; } xd_tmp = 0x80; IAPAL = u8_addrl_r; IAPAH = u16_addr>>8; set_IAPEN; set_APUEN; IAPCN = 0x21; while (xd_tmp !=0xFF) { IAPFD = *xd_tmp; set_IAPGO; IAPAL++; xd_tmp++; } clr_APUEN; clr_IAPEN;} /******************************************************************************************************************/ void main (void) { UINT8 datatemp;/* -------------------------------------------------------------------------*//* Dataflash use APROM area *//* APROM 0x3800~0x38FF demo as dataflash *//* Please use Memory window key in C:0x3800 to check earse result */ /* -------------------------------------------------------------------------*/ //call write byte write_DATAFLASH_BYTE (0x3881,0x55); write_DATAFLASH_BYTE (0x3882,0x56); write_DATAFLASH_BYTE (0x3855,0xaa); write_DATAFLASH_BYTE (0x3856,0x66);//call read byte datatemp = read_APROM_BYTE(0x3882); while(1);}
下面针对每一个调用函数进行讲解
void write_DATAFLASH_BYTE(UINT16 u16_addr,UINT8 u8_data){ UINT8 looptmp=0,u8_addrl_r; unsigned char code *cd_longaddr; unsigned char xdata *xd_tmp; //Check page start address u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { u8_addrl_r = 0; } else { u8_addrl_r = 0x80; }//Save APROM data to XRAM xd_tmp = 0x80; cd_longaddr = (u16_addr&0xff00)+u8_addrl_r; while (xd_tmp !=0x100) { *xd_tmp = *cd_longaddr; looptmp++; xd_tmp++; cd_longaddr++; }// Modify customer data in XRAM u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { xd_tmp = u8_addrl_r+0x80; } else { xd_tmp = u8_addrl_r+0; } *xd_tmp = u8_data;//Erase APROM DATAFLASH page IAPAL = u16_addr; IAPAH = u16_addr>>8; IAPFD = 0xFF; set_IAPEN; set_APUEN; IAPCN = 0x22; set_IAPGO; //Save changed RAM data to APROM DATAFLASH u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { u8_addrl_r =0; } else { u8_addrl_r = 0x80; } xd_tmp = 0x80; IAPAL = u8_addrl_r; IAPAH = u16_addr>>8; set_IAPEN; set_APUEN; IAPCN = 0x21; while (xd_tmp !=0xFF) { IAPFD = *xd_tmp; set_IAPGO; IAPAL++; xd_tmp++; } clr_APUEN; clr_IAPEN;}
上面这个函数，是对DATAFLASH EEPROM进行读写，有主函数给出地址和数据，由该函数进行处理
void write_DATAFLASH_BYTE(UINT16 u16_addr,UINT8 u8_data){ UINT8 looptmp=0,u8_addrl_r; unsigned char code *cd_longaddr; unsigned char xdata *xd_tmp; //Check page start address u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { u8_addrl_r = 0; } else { u8_addrl_r = 0x80; }//Save APROM data to XRAM xd_tmp = 0x80; cd_longaddr = (u16_addr&0xff00)+u8_addrl_r; while (xd_tmp !=0x100) { *xd_tmp = *cd_longaddr; looptmp++; xd_tmp++; cd_longaddr++; }// Modify customer data in XRAM u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { xd_tmp = u8_addrl_r+0x80; } else { xd_tmp = u8_addrl_r+0; } *xd_tmp = u8_data;//Erase APROM DATAFLASH page IAPAL = u16_addr; IAPAH = u16_addr>>8; IAPFD = 0xFF; set_IAPEN; set_APUEN; IAPCN = 0x22; set_IAPGO; //Save changed RAM data to APROM DATAFLASH u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { u8_addrl_r =0; } else { u8_addrl_r = 0x80; } xd_tmp = 0x80; IAPAL = u8_addrl_r; IAPAH = u16_addr>>8; set_IAPEN; set_APUEN; IAPCN = 0x21; while (xd_tmp !=0xFF) { IAPFD = *xd_tmp; set_IAPGO; IAPAL++; xd_tmp++; } clr_APUEN; clr_IAPEN;}
标红部分涉及到两个寄存器IAPL与IAPH，这起什么作用呢？看一下手册 由此可知，这两个寄存器是写入16位地址字节的，也就是说u8_addrl_r这个变量的含义是给寄存器提供地址，因此，需要一些数据的分析和处理，
u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { u8_addrl_r = 0; } else { u8_addrl_r = 0x80; }//Save APROM data to XRAM xd_tmp = 0x80; cd_longaddr = (u16_addr&0xff00)+u8_addrl_r; while (xd_tmp !=0x100) { *xd_tmp = *cd_longaddr; looptmp++; xd_tmp++; cd_longaddr++; }
Save APROM data to XRAM首先查看N76E003的数据手册得知这颗芯片的XRAM的大小为：768字节i ，即大小为0x300，另外还可知道Flash每一页的大小为128字节即0x80。这段历程划分区域到0X100（256）。
// Modify customer data in XRAM u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { xd_tmp = u8_addrl_r+0x80; } else { xd_tmp = u8_addrl_r+0; } *xd_tmp = u8_data;//Erase APROM DATAFLASH page IAPAL = u16_addr; IAPAH = u16_addr>>8; IAPFD = 0xFF; set_IAPEN; set_APUEN; IAPCN = 0x22; set_IAPGO;
Modify customer data in XRAM
在XRAM中修改客户数据
//Save changed RAM data to APROM DATAFLASH u8_addrl_r = u16_addr; if (u8_addrl_r<0x80) { u8_addrl_r =0; } else { u8_addrl_r = 0x80; } xd_tmp = 0x80; IAPAL = u8_addrl_r; IAPAH = u16_addr>>8; set_IAPEN; set_APUEN; IAPCN = 0x21; while (xd_tmp !=0xFF) { IAPFD = *xd_tmp; set_IAPGO; IAPAL++; xd_tmp++; } clr_APUEN; clr_IAPEN;}
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