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» SD 03: Append data

This example shows how to turn on the SD card. Append data at the end of the SD file.

Required Materials

1 x Waspmote
1 x Battery
1 x SD card
1 x MiniUSB wire

Notes

- Remember that only 8.3 SHORT FILE NAME are valid for files and directories
- Make sure Waspmote is switched off before inserting or removing the SD card. Otherwise, the SD card could be damaged.
- Waspmote must not be switched off or reseted while there are ongoing read or write operations in the SD card. Otherwise, the SD card could be damaged and data could be lost. If you suspect that there may be some ongoing SD operations, wait a while until they are completed.
- This example can be executed in Waspmote v12 and Waspmote v15

Code

/*  
 *  ------ [SD_03] - Append data to SD file -------- 
 *  
 *  Explanation: Turn on the SD card. Append data t the end of
 *  the SD file. 
 *  
 *  Copyright (C) 2016 Libelium Comunicaciones Distribuidas S.L. 
 *  http://www.libelium.com 
 *  
 *  This program is free software: you can redistribute it and/or modify 
 *  it under the terms of the GNU General Public License as published by 
 *  the Free Software Foundation, either version 3 of the License, or 
 *  (at your option) any later version. 
 *  
 *  This program is distributed in the hope that it will be useful, 
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of 
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 *  GNU General Public License for more details. 
 *  
 *  You should have received a copy of the GNU General Public License 
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>. 
 *  
 *  Version:           3.0
 *  Design:            David Gascón 
 *  Implementation:    Yuri Carmona
 */

// define file name: MUST be 8.3 SHORT FILE NAME
char filename[]="FILE3.TXT";

// define an example string
char data[]="hello"; 

// define variable
uint8_t sd_answer;


void setup()
{
  // open USB port
  USB.ON();
  USB.println(F("SD_3 example"));
  
  // Set SD ON
  SD.ON();
    
  // Delete file
  sd_answer = SD.del(filename);
  
  if( sd_answer == 1 )
  {
    USB.println(F("file deleted"));
  }
  else 
  {
    USB.println(F("file NOT deleted"));  
  }
    
  // Create file
  sd_answer = SD.create(filename);
  
  if( sd_answer == 1 )
  {
    USB.println(F("file created"));
  }
  else 
  {
    USB.println(F("file NOT created"));  
  } 
}


void loop()
{ 
  
  // 1 - It appends “he” in file indicating 2-byte length
  sd_answer = SD.append(filename, data, 2);
  
  if( sd_answer == 1 )
  {
    USB.println(F("\n1 - append \"he\" in file indicating 2-byte length"));
  }
  else
  {
    USB.println(F("\n1 - append error"));
  }
  
  // show file
  SD.showFile(filename);
  delay(1000);
  
  
  // 2 - It appends “hello” at the end of the file
  sd_answer = SD.append(filename, data);
  
  if( sd_answer == 1 )
  {
    USB.println(F("\n2 - appends \"hello\" at the end of the file"));
  }
  else 
  {
    USB.println(F("\n2 - append error"));
  }
  
  // show file
  SD.showFile(filename);
  delay(1000);
  
  
  // 3 - It appends data to file adding an End Of Line at the end of the string
  sd_answer = SD.appendln(filename,"goodbye");
  
  if( sd_answer == 1 )
  {
    USB.println(F("\n3 - append \"goodbye\" in file adding an EOL"));
  }
  else 
  {
    USB.println(F("\n3 - append error"));
  }
  
  // show file
  SD.showFile(filename);
  delay(5000); 
 
}



Output

E#
SD_3 example
file deleted
file created

1 - append "he" in file indicating 2-byte length

-------------------
he
-------------------

2 - appends "hello" at the end of the file

-------------------
hehello
-------------------

3 - append "first
second
third" in file adding an EOL

-------------------
hehellofirst
second
third

-------------------

1 - append "he" in file indicating 2-byte length

-------------------
hehellofirst
second
third
he
-------------------

2 - appends "hello" at the end of the file

-------------------
hehellofirst
second
third
hehello
-------------------

3 - append "first
second
third" in file adding an EOL

-------------------
hehellofirst
second
third
hehellofirst
second
third

-------------------

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