Cannot read flash memory after reset using FDS

[John12]

8738.sdk_config.h

Hi, I'm developing an application using internal flash memory.
I based on flash_fds example to implement this feature.
Now I can write and read data from flash.
My basic feature is when device reset It will read data from memory and it will blink led it data I want to read consist in flash memory. In this case I saved "hello !"

Here is my code

#define FILE_ID 0x0001    /* The ID of the file to write the records into. */
#define RECORD_KEY 0x1111 /* A key for the first record. */

// record using for write
fds_record_t record;
fds_record_desc_t record_desc;
fds_flash_record_t flash_record;
fds_find_token_t ftok;

bool flash_flag = false;
int flash_count = 0;
bool m_fds_initialized = false;

static char const m_hello[] = "hello !";

static void wait_for_fds_ready(void) {
  while (!m_fds_initialized) {
    power_manage();
  }
}

static void fds_evt_handler(fds_evt_t const *p_fds_evt) {
  switch (p_fds_evt->id) {
  case FDS_EVT_INIT:
    if (p_fds_evt->result == NRF_SUCCESS) {
      m_fds_initialized = true;
    }
    break;
  case FDS_EVT_WRITE:
    // NRF_LOG_INFO("write")
    flash_flag = true;
    memset(&ftok, 0x00, sizeof(fds_find_token_t));
    break;
  // case FDS_EVT_READ:
  default:
    break;
  }
}

uint8_t dataFromFlash[100];

int main(void) {
  bool erase_bonds;
  log_init();

  fds_register(fds_evt_handler);
  fds_init();
  wait_for_fds_ready();

  fds_record_open(&record_desc, &flash_record);
  sprintf(dataFromFlash, "%s", flash_record.p_data);
  if (strstr(dataFromFlash, m_hello) != NULL) {
    blinkLED(orange);

  } else {
    blinkLED(yellow);
  }
  fds_record_close(&record_desc);

  record.file_id = FILE_ID;
  record.key = RECORD_KEY;

  record.data.p_data = &m_hello;
  record.data.length_words = (sizeof(m_hello) + 3) / 4;
  fds_record_write(&record_desc, &record);

  while (flash_flag) {

    // while (fds_record_find(FILE_ID, RECORD_KEY, &record_desc, &ftok) == NRF_SUCCESS) {
    fds_record_open(&record_desc, &flash_record);
    sprintf(dataFromFlash, "%s", flash_record.p_data);
    NRF_LOG_INFO("%s", dataFromFlash);
    fds_record_close(&record_desc);
    break;
  }
  for (;;) {
  }
}

 
I attched my sdk_config.h

[Simonr]

Hi

First off, how exactly do you reset your device here? A regular pin reset with the DK or some other method. And where are you trying to write/read the stored data to/from after the reset? Do you get an error code indicating what might be going wrong?

Best regards,

Simon

[John12]

Hi Simonr, I use hard reset by button.
According to piece of code I attached.
Step by to step. Assume the first time my nRF have no data in flash memory.
Step 1:
From line 52->58:
- nRF copy data from flash and saved dataFromFlash
- then compare with m_hello which declared as "hello !" => false (because flash has no any data before was wroten before) => blink led yellow (line 56) 

Step 2: 
From line 60 -> 70
- nRF wrote to flash data a string "hello !" -> I read from flash and show at 72

Step 3: After reading the flash successfully => I press the DK button to hard reset the device => the program returns to step 1 => so in this step the nRF will flash the orange led (line 53) because the data from the flash has been pre-saved in the previous step

Do you understand my idea? I mean i wrote data at first time and next times nRF will blink orange LED instead of yellow LED because on first run the nRF has already written data to flash

I didn't get any error code, just only flash have no data to read.

[Simonr]

Hi again

So you also read it to make sure the "hello!" message is there right after you have written it to flash, correct? What SDK version are you using? As you can see in the fds example in the SDK we have added an array with FDS return values to get an idea of any errors that might occur. If you add that and some return values to your project as well we should get a better idea of what's going wrong. I'm not able to tell what the issue is just by looking at your main.c file and sdk_config.h I'm afraid. Some debugging will be required.

Best regards,

Simon

[John12]

Hi Simonr, thank for your support
Problem at hardware, so I can't use reset button.
When I try use my program for another board it worked.