M-arch (yateli M4) [at-start-f425 evaluation] No.05 flash

Preface

Today this is flash Reading and writing tests for ,AT32F425R8T7-7 Have 64K Of flash Space .

Flash memory structure

Flash controller （FMC）, It provides all the functions required by on-chip flash memory . generally speaking ,MCU Of Flash Include 4 Parts of ：

• Main storage （Main memory）, Its characteristic is readable and writable , Stored is the program ; If there is enough space , It can also be used to store data （ Parameters , Records, etc. ）.
• System storage area （System memory）, Some translations are called memory blocks , It's actually Boot Loader, read-only .
• One time storage area OTP（One Time Program）, It is characterized by only 1 Written as 0, Not by 0 Written as 1, Can be used to store protective or anti-counterfeiting content .
• Option bytes （Option bytes）, It stores some configuration data of the system , Load into register at power on .

Flash The reading and writing process and precautions are clearly written in the chip manual , I won't go into that ; If you're interested , You can face the manufacturer's API The interface is better than looking at , It would be better to understand .

AT32F425 Flash structure

stay flash In the private name of the partition , Remember that the following formula can be well understood ：

page （Page）< A sector （Sector） < block （Block,bank）< chip （Chip）

Generally, paging is the one with small capacity , Large capacity is divided into blocks + A sector .

FMC test

FMC The operation of is actually relatively simple , From the manufacturer API Are very mature , A few points to be noted ：

1. FMC You can't “ commit suicide ”, That is, it can't be written by the program itself , therefore FMC Can only write non program area Flash.
2. FMC Operation needs to be carried out first unlock, After the operation, remember lock.

Code ：

#ifdef AT32
#define fmc_sector_erase    flash_sector_erase
#define fmc_unlock          flash_unlock
#define fmc_lock            flash_lock
#define fmc_word_program    flash_word_program
#endif

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static void fmc_test(void)
{
#ifdef FMC_TEST
    #define FMC_TEST_DATA_COUNT 5
    static uint8_t fmc_test_flag = 0;
    uint32_t index = 0;
#if defined(GD32)
    uint32_t addr =  0x08100000;
    uint32_t sector = CTL_SECTOR_NUMBER_12;
#endif
#if defined(GD32M0)    
    uint32_t addr =  0x0803E000;
    uint32_t sector = addr;
    #define fmc_sector_erase fmc_page_erase
#endif
#ifdef STM32
    uint32_t addr =  0x08040000;
    uint32_t sector = addr;
#endif
#ifdef AT32
    uint32_t addr =  0x0800FC00;
    uint32_t sector = addr;
#endif    
    uint32_t *pdata = (uint32_t *)addr;
    int32_t fmc_state;

    if (fmc_test_flag)
    {
        return;
    }
    fmc_test_flag = 1;

    /* 1. before erase */
    printf("before erase,\tdata = ");
    for (index = 0; index < FMC_TEST_DATA_COUNT; index++)
    {
        printf("0x%X ", pdata[index]);
    }
    printf("\r\n");

    /* 2. after erase */
    fmc_unlock();
    fmc_state = fmc_sector_erase(sector);
    fmc_lock();
    printf("after erase[%d]\tdata = ", fmc_state);
    for (index = 0; index < FMC_TEST_DATA_COUNT; index++)
    {
        printf("0x%X ", pdata[index]);
    }
    printf("\r\n");

    /* 2. after program */
    fmc_unlock();
    for (index = 0; index < FMC_TEST_DATA_COUNT; index++)
    {
        fmc_state = fmc_word_program(addr, index+9);
        addr += 4;
        printf("programing [0x%0X] state = [%d]\r\n", addr, fmc_state);
    }
    fmc_lock();
    printf("after program,\tdata = ");
    for (index = 0; index < FMC_TEST_DATA_COUNT; index++)
    {
        printf("0x%X ", pdata[index]);
    }
    printf("\r\n");

#endif
}

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test result （AT32F425, The return value of normal state is 3）：

before erase, data = 0x9 0xA 0xB 0xC 0xD 
after erase[3] data = 0xFFFFFFFF 0xFFFFFFFF 0xFFFFFFFF 0xFFFFFFFF 0xFFFFFFFF 
programing [0x800FC04] state = [3]
programing [0x800FC08] state = [3]
programing [0x800FC0C] state = [3]
programing [0x800FC10] state = [3]
programing [0x800FC14] state = [3]
after program, data = 0x9 0xA 0xB 0xC 0xD 

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OTP and OB

adopt Keil You can view the debugging function of Flash Address data , Of course, it can also be read directly in the program .

AT32F425 The address range of is 0x1FFFF800 – 0x1FFFF9FF, The specific viewing results are slightly .