ESP8266 Community Forum

Posted: **Thu Aug 25, 2016 6:22 am**

Hi guys,

I'm using a NodeMCU board with embedded 12E.
I need a way to store short data that can be read back once the board has been rebooted.
So I tried to use File System but could not even pass this instruction: SPIFFS.begin();

If I use the following code, the program seems to always be stuck in the "begin" function :cry:

Nothing executes after that!

Code: Select all

bool ok = SPIFFS.begin();
  if (ok) {
    Serial.println("OK");
  }
  else {
    Serial.println("KO");
  }

Any idea??
By the way, if I just need to store short data (let's say a character) on FS, would it be possible (or simpler) to use EEPROM? What's the best practice?

Thanks

Posted: **Thu Aug 25, 2016 9:51 pm**

There is an example sketch that uses RTC memory. It can be used for storage between boots. Not power cycles though. I tried the example and it worked.
https://github.com/esp8266/Arduino/blob ... Memory.ino

EEPROM sample sketches can be found here -
https://github.com/esp8266/Arduino/tree ... M/examples

Posted: **Thu Aug 25, 2016 10:58 pm**

Try this

Code: Select all

// EEPROM Write then read

#include <ESP8266WiFi.h>
#include <EEPROM.h>

byte value;

void setup()
{
  WiFi.mode(WIFI_OFF);
  
  Serial.begin(115200);
  Serial.println(); 
    
  EEPROM.begin(512);

// remove comment to write
/*
//EEPROM.write(addr, val);
  EEPROM.write(0, 12);       
  EEPROM.write(1, 34);
  EEPROM.write(2, 56);
  EEPROM.write(3, 78);
  EEPROM.write(4, 90);
  EEPROM.write(5, 111);
  EEPROM.write(6, 222);
  EEPROM.write(7, 0);    
  EEPROM.commit();   
*/ 

  Serial.println(); 
  
  for (int i = 0; i < 14; i++) {
    value=EEPROM.read(i);
  Serial.print(i);
  Serial.print("\t");
  Serial.print(value, DEC);
  Serial.println();   
  }
    
}

void loop()
{
}

Posted: **Fri Aug 26, 2016 6:11 am**

Thanks rudy

According to the code comments it seems that RTC memory only works between deep sleep boots. I need a solution that works during power cycles also. EEPROM should be the solution then.

However I still don't understand why FS "begin" does not work ...
Do we have to call SPIFFS.format() before mounting FS with SPIFFS.begin() when first using FS?
I found this in the SPIFFS doc :

Formats the file system. May be called either before or after calling begin. Returns true if formatting was successful.

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