STM8做IAP(Bootloader)时在RAM中执行Flash块擦写函数问题
1、STM8的外设库驱动提供了很多代码，要求不高的话直接用库驱动即可
2、Flash块擦写速度快，但是必须要把函数放到RAM中执行（因为MCU的是NorFlash，普通的函数都是直接在Flash上执行的）
官方库如下
/**
* @brief Erases a block in the program or data memory.
* @note This function should be executed from RAM.
* @param FLASH_MemType : The type of memory to erase
* @param BlockNum : Indicates the block number to erase
* @retval None.
*/
IN_RAM(void FLASH_EraseBlock(uint16_t BlockNum, FLASH_MemType_TypeDef FLASH_MemType))
{
uint32_t startaddress = 0;
#if defined(STM8S105) || defined(STM8S005) || defined(STM8S103) || defined(STM8S003) || \
defined(STM8S001) || defined(STM8S903) || defined (STM8AF626x) || defined (STM8AF622x)
uint32_t PointerAttr *pwFlash;
#elif defined (STM8S208) || defined(STM8S207) || defined(STM8S007) || defined (STM8AF62Ax) || defined (STM8AF52Ax)
uint8_t PointerAttr *pwFlash;
#endif
/* Check parameters */
assert_param(IS_MEMORY_TYPE_OK(FLASH_MemType));
if(FLASH_MemType == FLASH_MEMTYPE_PROG)
{
assert_param(IS_FLASH_PROG_BLOCK_NUMBER_OK(BlockNum));
startaddress = FLASH_PROG_START_PHYSICAL_ADDRESS;
}
else
{
assert_param(IS_FLASH_DATA_BLOCK_NUMBER_OK(BlockNum));
startaddress = FLASH_DATA_START_PHYSICAL_ADDRESS;
}
/* Point to the first block address */
#if defined (STM8S208) || defined(STM8S207) || defined(STM8S007) || defined (STM8AF62Ax) || defined (STM8AF52Ax)
pwFlash = (PointerAttr uint8_t *)(MemoryAddressCast)(startaddress + ((uint32_t)BlockNum * FLASH_BLOCK_SIZE));
#elif defined(STM8S105) || defined(STM8S005) || defined(STM8S103) || defined(STM8S003) || \
defined(STM8S001) || defined (STM8S903) || defined (STM8AF626x) || defined (STM8AF622x)
pwFlash = (PointerAttr uint32_t *)(MemoryAddressCast)(startaddress + ((uint32_t)BlockNum * FLASH_BLOCK_SIZE));
#endif /* STM8S208, STM8S207 */
/* Enable erase block mode */
FLASH->CR2 |= FLASH_CR2_ERASE;
FLASH->NCR2 &= (uint8_t)(~FLASH_NCR2_NERASE);
#if defined(STM8S105) || defined(STM8S005) || defined(STM8S103) || defined(STM8S003) || \
defined(STM8S001) || defined(STM8S903) || defined (STM8AF626x) || defined (STM8AF622x)
*pwFlash = (uint32_t)0;
#elif defined (STM8S208) || defined(STM8S207) || defined(STM8S007) || defined (STM8AF62Ax) || \
defined (STM8AF52Ax)
*pwFlash = (uint8_t)0;
*(pwFlash + 1) = (uint8_t)0;
*(pwFlash + 2) = (uint8_t)0;
*(pwFlash + 3) = (uint8_t)0;
#endif
}
/**
* @brief Programs a memory block
* @note This function should be executed from RAM.
* @param FLASH_MemType : The type of memory to program
* @param BlockNum : The block number
* @param FLASH_ProgMode : The programming mode.
* @param Buffer : Pointer to buffer containing source data.
* @retval None.
*/
IN_RAM(void FLASH_ProgramBlock(uint16_t BlockNum, FLASH_MemType_TypeDef FLASH_MemType,
FLASH_ProgramMode_TypeDef FLASH_ProgMode, uint8_t *Buffer))
{
uint16_t Count = 0;
uint32_t startaddress = 0;
/* Check parameters */
assert_param(IS_MEMORY_TYPE_OK(FLASH_MemType));
assert_param(IS_FLASH_PROGRAM_MODE_OK(FLASH_ProgMode));
if(FLASH_MemType == FLASH_MEMTYPE_PROG)
{
assert_param(IS_FLASH_PROG_BLOCK_NUMBER_OK(BlockNum));
startaddress = FLASH_PROG_START_PHYSICAL_ADDRESS;
}
else
{
assert_param(IS_FLASH_DATA_BLOCK_NUMBER_OK(BlockNum));
startaddress = FLASH_DATA_START_PHYSICAL_ADDRESS;
}
/* Point to the first block address */
startaddress = startaddress + ((uint32_t)BlockNum * FLASH_BLOCK_SIZE);
/* Selection of Standard or Fast programming mode */
if(FLASH_ProgMode == FLASH_PROGRAMMODE_STANDARD)
{
/* Standard programming mode */ /*No need in standard mode */
FLASH->CR2 |= FLASH_CR2_PRG;
FLASH->NCR2 &= (uint8_t)(~FLASH_NCR2_NPRG);
}
else
{
/* Fast programming mode */
FLASH->CR2 |= FLASH_CR2_FPRG;
FLASH->NCR2 &= (uint8_t)(~FLASH_NCR2_NFPRG);
}
/* Copy data bytes from RAM to FLASH memory */
for(Count = 0; Count < FLASH_BLOCK_SIZE; Count++)
{
*((PointerAttr uint8_t*) (MemoryAddressCast)startaddress + Count) = ((uint8_t)(Buffer[Count]));
}
}默认IN_RAM是不打开，需要#define RAM_EXECUTION (1)
这样就可以用库里的块擦写函数了
3、分析一下库的代码，发现
擦除和写入命令差不多：首先操作FLASH->CR2和FLASH->NCR2，然后在相应的Flash上写数据，擦除写4个0即可
于是自己重写一下驱动
typedef byte (* flashProgramCodeInRamFun)(byte cr2, byte ncr2, word BlockNum, byte length, byte *Buffer);
__ramfunc byte LaunchFlashCommand(byte cr2, byte ncr2, word BlockNum, byte length, byte *Buffer)
{
uint16_t Count = 0;
uint32_t addr;
addr = BlockNum;
addr *= FLASH_BLOCK_SIZE;
addr += FLASH_PROG_START_PHYSICAL_ADDRESS;
/* Unlock program memory */
FLASH->PUKR = FLASH_RASS_KEY1;
FLASH->PUKR = FLASH_RASS_KEY2;
FLASH->CR2 |= cr2;
FLASH->NCR2 &= (uint8_t)(~ncr2);
for (Count = 0; Count < length; Count++)
{
*((PointerAttr uint8_t*) (uint32_t)addr + Count) = ((uint8_t)(Buffer[Count]));
}
while( (FLASH->IAPSR & (FLASH_IAPSR_EOP | FLASH_IAPSR_WR_PG_DIS)) == 0);
/* Lock memory */
FLASH->IAPSR &= (uint8_t)FLASH_MEMTYPE_PROG;
return FLASH_NO_ERROR;
}
byte PFlashEraseBlock(dword gAddr)
{
static byte data[]={0,0,0,0};
byte ret = 0;
dword blockNum = (gAddr - FLASH_PROG_START_PHYSICAL_ADDRESS) / FLASH_SECTOR_SIZE;
ret = ((flashProgramCodeInRamFun)DRIVER_ADDR)(FLASH_CR2_ERASE, FLASH_NCR2_NERASE, blockNum, 4, data);
return ret;
}
byte PFlashProg(dword gAddr, byte len, byte *pDat)
{
byte ret = 0;
dword blockNum = (gAddr - FLASH_PROG_START_PHYSICAL_ADDRESS) / FLASH_SECTOR_SIZE;
ret = ((flashProgramCodeInRamFun)DRIVER_ADDR)(FLASH_CR2_PRG, FLASH_NCR2_NPRG, blockNum, FLASH_SECTOR_SIZE, pDat);
return ret;
}（1）那么我想把地址直接传到LaunchFlashCommand中不用BlockNum行不行呢？
答案是分情况：如果参数是u16则完全没问题，适合32K以内的小容量MCU，如果是u32的参数则会出问题，程序跑飞
因此地址空间只有8000~FFFF=32K
（2）我想把函数放到固定地址上，参数是u16的BlockNum，不用__ramfunc 行不行？
答案也是分情况：如果在LaunchFlashCommand不用u32就可以，因此地址空间仍是32K
方法如下：
在icf中设置place at address mem: 0x0000CE00 { readonly section .funflash };
然后函数定义时：byte LaunchFlashCommand(byte cr2, byte ncr2, word BlockNum, byte length, byte *Buffer) @ ".funflash"
使用时手动将数据copy到ram中，长度在hex文件中查看
（3）为什么不能直接传u32的地址？为什么不用__ramfunc自己直接copy机器码，函数中使用u32就不行？
这问题我回答不上来，使用飞思卡尔的16位MCU也有类似的现象，自己指定函数地址，copy到ram，函数里如果使用u32则会出错。比较一下生成的hex文件，两种方式生成的机器码也不一样。
4、如何提取Flash驱动呢？
在汽车ECU上，OEM处于于安全考虑要求Flash的擦写函数不能保存在Flash中；执行Bootloader之前首先将Flash擦写函数（称之为驱动）发给MCU，MCU放到RAM里执行，用毕清空。
因此如何提取呢？
（1）查找map文件，找到LaunchFlashCommand的地址和长度
（2）仿真时，查看RAM窗口，找到LaunchFlashCommand部分的数据，选中复制
（3）将复制的数据做成s19或者hex文件