📄 fat16.c
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/*
* Copyright (c) 2004,北京博创兴业科技有限公司
* All rights reserved.
*
* 文件名称：fat16.c
* 文件标识：fat16
* 摘 要：fat操作的函数实现
*
* 当前版本：2.0
* 作 者：Kent
* 完成日期：2004年5月20日
*
* 取代版本：1.1
* 原作者 ：Frank
* 完成日期：2003年8月10日
*/
#include "Fat16.h"
#include "Flash.h"
#include "uart.h"
unsigned char Page_Buf[512];
//数据结构与全局变量定义
void Delay(long int nLength)
{
long int i;
for (i=0; i<nLength; i++)
{
i=i;
}
}
code unsigned char BPB_Data[512] = {
0xeb, 0x3c, 0x90,// Offset_U8_BS_jmpBoot 0
'F', 'r', 'a', 'n', 'k', 'w', 'x', 'j',// Offset_U8_BS_OEMName 3
0x00, 0x02,// Offset_short int_BPB_BytsPerSec 11 //Count of bytes per sector. This value may take on only the //
//512 //following values: 512, 1024, 2048 or 4096. If maximum //
//compatibility is desired, only the value 512 should be used.//
64,// Offset_U8_BPB_SecPerClus 13 //Number of sectors per allocation unit. This value must be a //
//power of 2 that is greater than 0. The legal values are 1, //
// 2, 4, 8, 16, 32, 64,and 128. //
0x1, 0x00,// Offset_short int_BPB_RsvdSecCnt 14 //Number of reserved sectors in the Reserved region of the //
//volume starting at the first sector of the volume.For FAT32 //
//volumes, this value is typically 32. //
0x02,// Offset_U8_BPB_NumFATs 16 //The count of FAT data structures on the volume. //
0xb0, 0x03,// Offset_short int_BPB_RootEntCnt 17 //Is only useful for FAT12 and FAT16 volumes. //
// //For FAT32 volumes,this field must be set to 0. //
//通过调整文件项为03b0，从而使数据扇区刚好从Block2Sector0开始，但
//文件分区表中根目录区并为标记为已占用。数据实际从Block4Sector0开始
//59+1+4 = 64个page，正好一个cluster
0xea, 0x7f,// Offset_short int_BPB_TotSec16 19 //For FAT12 and FAT16 volumes, this field contains the sector //
//count, and BPB_TotSec32 is 0 if the total sector count fits //
//(is less than 0x10000). //
0xf8,// Offset_U8_BPB_Media 21 //0xF8 is the standard value for fixed(non-removable) media. //
//For removable media, 0xF0 is frequently used. //
0x02, 0x00,// Offset_short int_BPB_FATSz16 22 //This field is FAT12/FAT16 16bit count of sectors occupied by//
// 1 FAT.On FAT32 volumes this field must be 0, and BPB_FATSz32//
//contains the FAT size count. //
0x00, 0x00,// Offset_short int_BPB_SecPerTrk 24 //Sectors per track for interrupt 0x13. This field is only //
//relevant for media that have a geometry (volume is broken //
//down into tracks by multiple heads and cylinders) and are //
//visible on interrupt 0x13.This field contains the //
//"sectors per track" geometry value. //
0x00, 0x00,// Offset_short int_BPB_NumHeads 26 //Number of heads for interrupt 0x13. This field is relevant //
//as discussed earlier for BPB_SecPerTrk. //
0x01, 0x00, 0x00, 0x00,// Offset_U32_BPB_HiddSec 28 //Count of hidden sectors preceding the partition that //
//contains this FAT volume. //
0x00, 0x00, 0x00, 0x00,// Offset_U32_BPB_TotSec32 32 //This field is the new 32-bit total count of sectors on the //
//volume. This count includes the count of all sectors in all //
//four regions of the volume. This field can be 0; if it is 0,//
//then BPB_TotSec16 must be non-zero. For FAT32 volumes, this //
//field must be non-zero. For FAT12/FAT16 volumes, this field //
//contains the sector count if BPB_TotSec16 is 0 (count is //
//greater than or equal to 0x10000).//
0x00,// Offset_U8_BS_DrvNum 36 //This field is the FAT32 32-bit count of sectors occupied by //
//根据该值得到FAT的大小// //ONE FAT. BPB_FATSz16 must be 0. //
0x00,// Offset_U8_BS_Reserved 37 // Bits 0-3 -- Zero-based number of active FAT.Only valid //
// if mirroring is disabled. //
// Bits 4-6 -- Reserved. //
// Bit 7 -- 0 means the FAT is mirrored at runtime into //
// all FATs. //
// -- 1 means only one FAT is active;it is the one//
// referenced in bits 0-3. //
// Bits 8-15 -- Reserved. //
0x29,// Offset_U8_BS_BootSig 38 //High byte is major revision number. //
//Low byte is minor revision number. //
'N', 'A', 'M', 'E',// Offset_U32_BS_VolID 39 //This is set to the cluster number of the first cluster of //
//根据该值得到ROOT的地址// //the root directory, usually 2 but not required to be 2. //
'N', 'O', ' ', 'N', 'A', 'M', 'E', ' ', ' ', ' ', ' ',// Offset_U2048_BS_VolLab 43 //Sector number of FSINFO structure in the reserved area of //
//the FAT32 volume.Usually 1. //
'F', 'A', 'T', '1', '6', ' ', ' ', ' ',// Offset_U256_BS_FilSysType 54 //If non-zero, indicates the sector number in the reserved //
//area of the volume of a copy of the boot record. //
//Executable Code
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,0 ,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0x00,//active partion
0x00,//head
0x00,//partion begin
0x00,//cylinder
0x06,//is partion used
0x00,//end head
0x00,//partion end
0x00,//end cylinder
0x00, 0x00, 0x00, 0x00,
0x00, 0x80, 0x00, 0x00,//fist partion
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,//second partion
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,//third partion
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,//forth partion
0x55, 0xAA // Offset_short int_Signature 510 //0x55AA
};
void WriteMBR2Flash(void)
{
if (Check_Flash_Id() == KM29U128_ID)
{
WritePage(Root_Cluster, BPB_Sector, BPB_Data);
}
else
printu("\nKM29U128 is Not Found!");
}
void CreatFAT12(void) //每一个簇对应一个表项
{
short int i;
unsigned char *FAT = Page_Buf;
for (i=0; i<512; i++)
{
FAT[i] = 0x00;
}
//disk type lower byte is equal to Offset_U8_BPB_Media
FAT[0] = 0xf8;
FAT[1] = 0xff;//system occupied the first cluster
FAT[2] = 0xff;
FAT[3] = 0x7f; //???????? 应该是fat16
if (Check_Flash_Id() == KM29U128_ID)
{
WritePage(Root_Cluster, Fat_Sector, FAT); //Sector 1 of Fat16 //FAT指针是否变化?
WritePage(Root_Cluster, Fat_Sector + 2, FAT); //Sector 1 of Fat16
FAT[0] = FAT[1] = FAT[2] = FAT[3] = 0x00;
WritePage(Root_Cluster, Fat_Sector + 1, FAT); //Sector 2 of Fat16
WritePage(Root_Cluster, Fat_Sector + 3, FAT); //Sector 2 of Fat16
//函数的形参和实参具有以下特点：1.形参变量只有在被调用时才分配内存单元，在调用结束时，?即刻?
//释放所分配的内存单元。因此，形参只有在函数内部有效。?函数?
//调用结束返回主调函数后则不能再使用该形参变量。?
// 2.实参可以是常量、变量、表达式、函数等，?无论实参是何种类型?
//的量，在进行函数调用时，它们都必须具有确定的值，?以便把这?
//些值传送给形参。?因此应预先用赋值，输入等办法使实参获得确?
//定值。
3.实参和形参在数量上，类型上，顺序上应严格一致，?否则会发生?
??“类型不匹配”的错误。?
4.函数调用中发生的数据传送是单向的。?即只能把实参的值传送给?
??形参，而不能把形参的值反向地传送给实参。?因此在函数调用过?
??程中，形参的值发生改变，而实参中的值不会变化。例5.3可以说?
??明这个问题
}
else
{
printu("\nKM29U128 is Not Found!");
}
}
void CreatDirectoryEntry(void)
{
long int i;
unsigned char *Directory_Enties = Page_Buf;
for (i=0; i<512; i++)
{
Directory_Enties[i] = 0x00;
}
if (Check_Flash_Id() == KM29U128_ID)
{
for (i=0; i<35; i++) //35是怎么选的澹⌨️ 快捷键说明
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