前言 暫存器介紹

0 .1 Non-Volatile Memory Controller (NVMC)

Functional description
The Non-volatile Memory Controller (NVMC) is used for writing and erasing Non-volatile Memory (NVM).
Before a write can be performed the NVM must be enabled for writing in CONFIG.WEN. Similarly, before an
erase can be performed the NVM must be enabled for erasing in CONFIG.EEN. The user must make sure
that writing and erasing is not enabled at the same time, failing to do so may result in unpredictable behavior.

0.2 Factory Information Configuration Registers (FICR)

Functional description
Factory Information Configuration Registers are pre-programmed in factory and cannot be erased by the
user. These registers contain chip specific information and configuration

1  確定寫入flash 的位置

     通過FICR 暫存器，讀取nrf51822的flash page size 和 the number of pages

    uint32_t * addr;    

    uint32_t   pg_size;
    uint32_t   pg_num;
    pg_size = NRF_FICR->CODEPAGESIZE;
    pg_num  = NRF_FICR->CODESIZE - 1;  // Use last page in flash

2  擦除flash page（寫入資料前，先把該page資料擦除）

        // Erase page:
        flash_page_erase(addr);
 

/** @brief Function for erasing a page in flash.
 *
 * @param page_address Address of the first word in the page to be erased.
 */
static void flash_page_erase(uint32_t * page_address)
{
    // Turn on flash erase enable and wait until the NVMC is ready:
    NRF_NVMC->CONFIG = (NVMC_CONFIG_WEN_Een << NVMC_CONFIG_WEN_Pos);

    while (NRF_NVMC->READY == NVMC_READY_READY_Busy)
    {
        // Do nothing.
    }

    // Erase page:
    NRF_NVMC->ERASEPAGE = (uint32_t)page_address;

    while (NRF_NVMC->READY == NVMC_READY_READY_Busy)
    {
        // Do nothing.
    }

    // Turn off flash erase enable and wait until the NVMC is ready:
    NRF_NVMC->CONFIG = (NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos);

    while (NRF_NVMC->READY == NVMC_READY_READY_Busy)
    {
        // Do nothing.
    }
}

flash_word_write(++addr, (uint32_t)patwr);

/** @brief Function for filling a page in flash with a value.
 *
 * @param[in] address Address of the first word in the page to be filled.
 * @param[in] value Value to be written to flash.
 */
static void flash_word_write(uint32_t * address, uint32_t value)
{
    // Turn on flash write enable and wait until the NVMC is ready:
    NRF_NVMC->CONFIG = (NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos);

    while (NRF_NVMC->READY == NVMC_READY_READY_Busy)
    {
        // Do nothing.
    }

    *address = value;

    while (NRF_NVMC->READY == NVMC_READY_READY_Busy)
    {
        // Do nothing.
    }

    // Turn off flash write enable and wait until the NVMC is ready:
    NRF_NVMC->CONFIG = (NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos);

    while (NRF_NVMC->READY == NVMC_READY_READY_Busy)
    {
        // Do nothing.
    }
}