#include "flash.h"

void flash_unlock(){

    // Check if flash is locked
    if(!(FLASH->CR & FLASH_CR_LOCK)) {
        return; // Already unlocked
    }

    // Write flash key sequence to unlock
    FLASH->KEYR = 0x45670123;  // First key
    FLASH->KEYR = 0xCDEF89AB;  // Second key

}

void flash_lock() {
    if(FLASH->CR & FLASH_CR_LOCK) {
        return; // Already locked
    }
    FLASH->CR |= FLASH_CR_LOCK; // Lock flash memory
}

void erase_sector(uint8_t sector){
    
    // Wait if flash is busy
    while(FLASH_BUSY);

    // Check if flash is locked and unlock if needed
    if(FLASH->CR & FLASH_CR_LOCK) {
        flash_unlock();
    }

    // Set sector erase bit and sector number
    FLASH->CR |= FLASH_CR_SER;
    FLASH->CR &= ~FLASH_CR_SNB;
    FLASH->CR |= (sector << FLASH_CR_SNB_Pos) & FLASH_CR_SNB_Msk;

    // Start erase
    FLASH->CR |= FLASH_CR_STRT;

    // Wait for erase to complete
    while(FLASH_BUSY);
    
    // Clear sector erase bit
    FLASH->CR &= ~FLASH_CR_SER;

}

void flash_program_word(uint32_t address,uint32_t data,uint32_t byte_len){

    // Wait if flash is busy
    while(FLASH_BUSY);
    // Check if flash is locked and unlock if needed
    if(FLASH->CR & FLASH_CR_LOCK) {
        flash_unlock();
    }

    // Set program bit 32bit programm size and  Write data to address
    if(byte_len == 1) {
        FLASH_8BYTE;
        FLASH->CR |= FLASH_CR_PG;
        *(volatile uint8_t*)address = (uint8_t)data;
    } else {
        FLASH_32BYTE;
        FLASH->CR |= FLASH_CR_PG;
        *(volatile uint32_t*)address = data;
    }

    // Wait for programming to complete
    while(FLASH_BUSY);

    // Clear program bit
    FLASH->CR &= ~FLASH_CR_PG;

}

uint8_t flash_read_word(uint32_t address){
   
    // Check if address is valid
    if(address < FLASH_BASE || address > FLASH_END) {
        return 0;
    }

    // Read byte from flash memory
    return *((volatile uint8_t*)address);

}
    // Wait if flash