Flash program memory and data EEPROM
1、簡介
STM8S內部的FLASH程序存儲器和數據EEPROM是由一組通用寄存器來控制的;所以我們可以通過這些通用寄存器來編程或擦除存儲器的內容、設置寫保護、或者配置特定的低功耗模式。我們也可以自己對器件的 option byte 進行編程。在這裏我們只簡單的講解如何對STM8S內部的數據存儲區域(data memory)進行寫操作、讀操作、擦除操作。
2、存儲架構圖
STM8S內部存儲包括:FLASH程序存儲器(FLASH program memory)和數據EEPROM(DATA EEPROM);
(1)數據EEPROM又包括:
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- 數據存儲區域(DATA MEMORY):指定從地址0x00 4000開始,其中包括 [1 block] 的option byte,數據存儲區域用於存儲應用數據;
(2)FLASH程序存儲器又包括:
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- 用戶啟動區域(USER BOOT CODE):指定從地址0x00 8000開始,其中包括UBC option bytes和 [128 byte] 的中斷矢量(interrupt vectors);
- 程序存儲區域(MAIN PROGRAM):用於存儲應用程序代碼;
所以我們的操作是在DATA MEMORY裏面,在該區域的指定地址進行讀取內容、寫入內容、擦除內容。
3、操作方法
(1)FLASH_ReadByte( ADDRESS ):讀取地址ADDRESS處的1字節內容
(2)FLASH_ProgramByte( ADDRESS , DATA ):寫1字節的內容到地址ADDRESS處
(3)FLASH_EraseByte( ADDRESS ):在地址ADDRESS處刪除1字節的內容
4、操作步驟
使用操作前的配置
(1)配置選擇編程時間,選擇標準模式;
(2)解除數據存儲區域的寫保護;
說明:UBC和DATA MEMORY都有寫保護,其中UBC的寫保護是永遠無法解鎖的,而DATA MEMORY的寫保護是可以通過連續寫入兩個MASS密鑰值來解除該區域的寫保護的;第一個密鑰為0x56,第二個密鑰為0xAE;只有當兩個密鑰輸入正確(輸入到寄存器FLASH_DUKR中)且輸入密鑰的先後順序正確時,才會解除寫保護;否則該區域在下一次系統復位之前都將一直保持寫保護狀態。
(3)讀取、寫入、擦除等操作;
5、代碼實現
1 /* Includes ------------------------------------------------------------------*/ 2 #include "stm8s.h" 3 4 /* Private typedef -----------------------------------------------------------*/ 5 typedef enum { FAILED = 0, PASSED = !FAILED} TestStatus; 6 7 /* Private variables ---------------------------------------------------------*/ 8 __IO TestStatus OperationStatus; 9 10 11 /** 12 * @brief How to Read / Write / Erase one Byte on FLASH memory. 13 * @par Examples description 14 * - Read one byte at address 0x40A5 15 * - Write its complement value at address + 1 16 * - Check programed value 17 * - Erase 2 byte (address 40A5 & 40A6) 18 * - Check the 2 bytes value is 0x00. 19 * @param None 20 * @retval None 21 */ 22 void main(void) 23 { 24 25 uint8_t val = 0x00, val_comp = 0x00; 26 uint32_t add = 0x00; 27 28 /* Define FLASH programming time */ 29 //Standard programming time fixed at 1/2 tprog 30 FLASH_SetProgrammingTime(FLASH_PROGRAMTIME_STANDARD); 31 32 /* Unlock Data memory */ 33 //compare to two hardware key value: 0x56 and 0xAE 34 FLASH_Unlock(FLASH_MEMTYPE_DATA); 35 36 /* Read a byte at a specified address */ 37 add = 0x40A5; 38 //read one byte from the address 39 val = FLASH_ReadByte(add); 40 41 /* Program complement value (of previous read byte) at previous address + 1 */ 42 val_comp = (uint8_t)(~val); 43 //modify one byte at the address 44 FLASH_ProgramByte((add + 1), val_comp); 45 46 /* Check program action */ 47 val = FLASH_ReadByte((add + 1)); 48 if (val != val_comp) 49 { 50 /* Error */ 51 OperationStatus = FAILED; 52 /* OperationStatus = PASSED, if the data written/read to/from DATA EEPROM memory is correct */ 53 /* OperationStatus = FAILED, if the data written/read to/from DATA EEPROM memory is corrupted */ 54 while (1) 55 { 56 } 57 } 58 59 /* Erase byte at a specified address & address + 1 */ 60 //erase one byte at the address 61 FLASH_EraseByte(add); 62 FLASH_EraseByte((add + 1)); 63 /* Erase action */ 64 val = FLASH_ReadByte(add); 65 val_comp = FLASH_ReadByte((add + 1)); 66 if ((val != 0x00) & (val_comp != 0x00)) 67 { 68 /* Error */ 69 OperationStatus = FAILED; 70 /* OperationStatus = PASSED, if the data written/read to/from DATA EEPROM memory is correct */ 71 /* OperationStatus = FAILED, if the data written/read to/from DATA EEPROM memory is corrupted */ 72 while (1) 73 { 74 } 75 } 76 77 /* Pass */ 78 OperationStatus = PASSED; 79 /* OperationStatus = PASSED, if the data written/read to/from DATA EEPROM memory is correct */ 80 /* OperationStatus = FAILED, if the data written/read to/from DATA EEPROM memory is corrupted */ 81 while (1) 82 { 83 } 84 }FLASH
Flash program memory and data EEPROM