Yung-Chieh Lo / F042K6_Flash

To access the internal flash of STM32F042K6.

This library provides a Partition class used to segment the STM32F042K6 internal flash so that the caller can read/write/erase the partition.

Examples

    FlashPartition config(0x7c00, 0x400);

    uint8_t buf[16];
    config.Read(address, buf, sizeof(buf));

    config.EraseAll();
    config.Write(address, buf, sizeof(buf));

f042k6_flash.cpp

Committer:
yjlou
Date:
2017-09-11
Revision:
1:7a490a05943a
Parent:
0:a71e3b72379a

File content as of revision 1:7a490a05943a:

#include "f042k6_flash.h"

#include <string.h>

// Read flash content in this partition.
void FlashPartition::Read(uint32_t offset, char* buf, size_t len) {
    memcpy(buf, (void*)(USER_FLASH_AREA_START + start_addr_ + offset), len);
}

// Write flash content into this partition.
// Returns true for success.
bool FlashPartition::Write(uint32_t offset, const char* buf, size_t len) {
    UnlockControlRegister();

    if (*REG32(FLASH_SR) & SR_BSY) {
        return false;
    }

    *REG32(FLASH_CR) |= CR_PG;
    
    const uint16_t* src = (uint16_t*)buf;
    uint16_t* dst = (uint16_t*)(USER_FLASH_AREA_START + start_addr_ + offset);
    for (int i = 0; i < (len + 1) / 2; i++) {
        *(dst++) = *(src++);
        while (*REG32(FLASH_SR) & SR_BSY);
    }

    *REG32(FLASH_CR) &= ~CR_PG;

    return true;
}

// Erase whole partition
// Returns true for success.
bool FlashPartition::EraseAll() {
    UnlockControlRegister();
    
    if (*REG32(FLASH_SR) & SR_BSY) {
        return false;
    }

    *REG32(FLASH_CR) |= CR_PER;
    
    for (uint32_t page = USER_FLASH_AREA_START + start_addr_;
         page < (USER_FLASH_AREA_START + start_addr_ + size_);
         page += kFlashPageInBytes) {
        *REG32(FLASH_AR) = page;
        *REG32(FLASH_CR) |= CR_STRT;
        while (*REG32(FLASH_SR) & SR_BSY);
    }
    *REG32(FLASH_CR) &= ~CR_PER;

    return true;
}

void FlashPartition::UnlockControlRegister() {
    if (*REG32(FLASH_CR) & CR_LOCK) {
        *REG32(FLASH_KEYR) = 0x45670123;
        *REG32(FLASH_KEYR) = 0xCDEF89AB;
    }
}