1.1参考文档及路径
- DUI0459F_02_mdk_fromelf_user_guide.pdf；
2.Cortex-M3 技术参考手册.pdf;
1.2 Flash Loader简介
平时我们使用的仿真器（ST-LINK,J-LINK）并不是直接将数据烧写到芯片的flash存储器中。而是通过一段专门的程序Flash Loader。它实际上是一段主要用来擦除，写入Flash的小程序。从原理上来说就是仿真器先下载Flash Loader到RAM中，然后操作内核寄存器调用Flash Loader函数集。当函数返回，会产生一个中断，仿真器就会知道函数已经完成，进而继续调用Flash Loader。
简单的说，仿真器从Flash Loader调用函数来实现对芯片的烧写，擦除操作。将程序下载到flash，有两种方式：
- 直接操作Flash存储器
通过调试接口（DAP）操作芯片相关的FLASH寄存器，具体怎么做需要查阅芯片的相关说明文档。
2. 间接操作Flash存储器
A）下载Flash Loader到RAM中；
B）将应用程序的映像下载到RAM缓冲区中；
C）Flash Loader通过仿真器启动，将RAM Buffer里读出的数据编程到Flash中；
D）现在，应用程序的映像文件就在Flash存储器中了。
1.3 Flash Loader编写
根据keil提供的模板C:\Keil_v5\ARM\Flash\_Template，至少需要以下3个文件：
A） FlashDev.c，Device Decription,是一个结构体变量，里面定义的是Flash相关信息
1 /***********************************************************************/ 2 /* This file is part of the ARM Toolchain package */ 3 /* Copyright (c) 2010 Keil - An ARM Company. All rights reserved. */ 4 /***********************************************************************/ 5 /* */ 6 /* FlashDev.C: Device Description for New Device Flash */ 7 /* */ 8 /***********************************************************************/ 9 10 #include "..\FlashOS.H" // FlashOS Structures 11 12 13 struct FlashDevice const FlashDevice = { 14 FLASH_DRV_VERS, // Driver Version, do not modify! 15 "New Device 256kB Flash", // Device Name 16 ONCHIP, // Device Type 17 0x00000000, // Device Start Address 18 0x00040000, // Device Size in Bytes (256kB) 19 1024, // Programming Page Size 20 0, // Reserved, must be 0 21 0xFF, // Initial Content of Erased Memory 22 100, // Program Page Timeout 100 mSec 23 3000, // Erase Sector Timeout 3000 mSec 24 25 // Specify Size and Address of Sectors 26 0x002000, 0x000000, // Sector Size 8kB (8 Sectors) 27 0x010000, 0x010000, // Sector Size 64kB (2 Sectors) 28 0x002000, 0x030000, // Sector Size 8kB (8 Sectors) 29 SECTOR_END 30 };
B）FlashPrg.c，Program Functions实现Flash的初始化，擦除，写等函数
1 /***********************************************************************/ 2 /* This file is part of the ARM Toolchain package */ 3 /* Copyright (c) 2010 Keil - An ARM Company. All rights reserved. */ 4 /***********************************************************************/ 5 /* */ 6 /* FlashDev.C: Flash Programming Functions adapted */ 7 /* for New Device 256kB Flash */ 8 /* */ 9 /***********************************************************************/ 10 11 #include "..\FlashOS.H" // FlashOS Structures 12 /* 13 * Initialize Flash Programming Functions 14 * Parameter: adr: Device Base Address 15 * clk: Clock Frequency (Hz) 16 * fnc: Function Code (1 - Erase, 2 - Program, 3 - Verify) 17 * Return Value: 0 - OK, 1 - Failed 18 */ 19 20 int Init (unsigned long adr, unsigned long clk, unsigned long fnc) { 21 22 /* Add your Code */ 23 return (0); // Finished without Errors 24 } 25 26 27 /* 28 * De-Initialize Flash Programming Functions 29 * Parameter: fnc: Function Code (1 - Erase, 2 - Program, 3 - Verify) 30 * Return Value: 0 - OK, 1 - Failed 31 */ 32 33 int UnInit (unsigned long fnc) { 34 35 /* Add your Code */ 36 return (0); // Finished without Errors 37 } 38 39 40 /* 41 * Erase complete Flash Memory 42 * Return Value: 0 - OK, 1 - Failed 43 */ 44 45 int EraseChip (void) { 46 47 /* Add your Code */ 48 return (0); // Finished without Errors 49 } 50 51 52 /* 53 * Erase Sector in Flash Memory 54 * Parameter: adr: Sector Address 55 * Return Value: 0 - OK, 1 - Failed 56 */ 57 58 int EraseSector (unsigned long adr) { 59 60 /* Add your Code */ 61 return (0); // Finished without Errors 62 } 63 64 65 /* 66 * Program Page in Flash Memory 67 * Parameter: adr: Page Start Address 68 * sz: Page Size 69 * buf: Page Data 70 * Return Value: 0 - OK, 1 - Failed 71 */ 72 73 int ProgramPage (unsigned long adr, unsigned long sz, unsigned char *buf) { 74 75 /* Add your Code */ 76 return (0); // Finished without Errors 77 }
C）FlashOS.h， 结构体定义
1 /* ----------------------------------------------------------------------------- 2 * Copyright (c) 2014 ARM Ltd. 3 * 4 * This software is provided \'as-is\', without any express or implied warranty. 5 * In no event will the authors be held liable for any damages arising from 6 * the use of this software. Permission is granted to anyone to use this 7 * software for any purpose, including commercial applications, and to alter 8 * it and redistribute it freely, subject to the following restrictions: 9 * 10 * 1. The origin of this software must not be misrepresented; you must not 11 * claim that you wrote the original software. If you use this software in 12 * a product, an acknowledgment in the product documentation would be 13 * appreciated but is not required. 14 * 15 * 2. Altered source versions must be plainly marked as such, and must not be 16 * misrepresented as being the original software. 17 * 18 * 3. This notice may not be removed or altered from any source distribution. 19 * 20 * 21 * $Date: 14. Jan 2014 22 * $Revision: V1.00 23 * 24 * Project: FlashOS Headerfile for Flash drivers 25 * --------------------------------------------------------------------------- */ 26 27 /* History: 28 * Version 1.00 29 * Initial release 30 */ 31 32 #define VERS 1 // Interface Version 1.01 33 34 #define UNKNOWN 0 // Unknown 35 #define ONCHIP 1 // On-chip Flash Memory 36 #define EXT8BIT 2 // External Flash Device on 8-bit Bus 37 #define EXT16BIT 3 // External Flash Device on 16-bit Bus 38 #define EXT32BIT 4 // External Flash Device on 32-bit Bus 39 #define EXTSPI 5 // External Flash Device on SPI 40 41 #define SECTOR_NUM 512 // Max Number of Sector Items 42 #define PAGE_MAX 65536 // Max Page Size for Programming 43 44 struct FlashSectors { 45 unsigned long szSector; // Sector Size in Bytes 46 unsigned long AddrSector; // Address of Sector 47 }; 48 49 #define SECTOR_END 0xFFFFFFFF, 0xFFFFFFFF 50 51 struct FlashDevice { 52 unsigned short Vers; // Version Number and Architecture 53 char DevName[128]; // Device Name and Description 54 unsigned short DevType; // Device Type: ONCHIP, EXT8BIT, EXT16BIT, ... 55 unsigned long DevAdr; // Default Device Start Address 56 unsigned long szDev; // Total Size of Device 57 unsigned long szPage; // Programming Page Size 58 unsigned long Res; // Reserved for future Extension 59 unsigned char valEmpty; // Content of Erased Memory 60 61 unsigned long toProg; // Time Out of Program Page Function 62 unsigned long toErase; // Time Out of Erase Sector Function 63 64 struct FlashSectors sectors[SECTOR_NUM]; 65 }; 66 67 #define FLASH_DRV_VERS (0x0100+VERS) // Driver Version, do not modify! 68 69 // Flash Programming Functions (Called by FlashOS) 70 extern int Init (unsigned long adr, // Initialize Flash 71 unsigned long clk, 72 unsigned long fnc); 73 extern int UnInit (unsigned long fnc); // De-initialize Flash 74 extern int BlankCheck (unsigned long adr, // Blank Check 75 unsigned long sz, 76 unsigned char pat); 77 extern int EraseChip (void); // Erase complete Device 78 extern int EraseSector (unsigned long adr); // Erase Sector Function 79 extern int ProgramPage (unsigned long adr, // Program Page Function 80 unsigned long sz, 81 unsigned char *buf); 82 extern unsigned long Verify (unsigned long adr, // Verify Function 83 unsigned long sz, 84 unsigned char *buf);
绝大多数的Flash Loader可以去keil的官网上下载。
