Issue on writing to a file

[xristod]

Dear All, I need your advice on a problem I have when I am deleting and creating a file writing an incremented number into it. If you check my code below, when I press "c" the file "myLog.txt" is deleted and a new one is created writing an incremented number into it. Up to number 9 everything works fine but when it is writing number 10 then it freezes ....

Delete file ... File deleted! File created! Enter command mode! Read of new file:

8

Delete file ... File deleted! File created! Enter command mode! Read of new file:

9

Delete file ... File deleted! File created! Enter command mode!

When I opened the file from the PC and checked the number written I noticed that it was not just "10" but "10". In addition I would like to let you know that the method I have implemented for using the command "write File OFFSET" is not working and I do not know what I have done wrong. Finally could you please let me know why each time I create a file I have to use "gotoCommandMode();" since I have declared it in the "setup()"? Best, George

The code I have used is the following with some modifications of the original one provided by Sparkfun....

include

//-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- //Connect TXO of OpenLog to pin 3, RXI to pin 2 SoftwareSerial OpenLog(3, 2); //Soft RX on 3, Soft TX out on 2 //SoftwareSerial(rxPin, txPin)

byte resetOpenLog = A1; //This pin resets OpenLog. Connect pin 4 to pin GRN on OpenLog.

int number = 0; String filename = "myLog.txt";

void setup() {

Serial.begin(9600);

setupOpenLog(); //Resets logger and waits for the '<' I'm alive character Serial.println("OpenLog online"); gotoCommandMode(); //Puts OpenLog in command mode

createFile(filename); OpenLog.print(String(number)); gotoCommandMode(); //Puts OpenLog in command mode

String str = readFile(filename); Serial.println("Read of new file: "); Serial.println(str);

}

void loop() {

if (Serial.available()) { char c = Serial.read();

if (c == 'c')
{
  ++number;

  Serial.println("Delete file ...");
  deleteFile(filename);
  Serial.println("File deleted!");
  createFile(filename);
  Serial.println("File created!");
  //  writeFileOffset(filename, 0);

  OpenLog.print(String(number));

  Serial.println("Enter command mode!");
  gotoCommandMode(); //Puts OpenLog in command mode

  Serial.println("Read of new file: ");
  String str = readFile(filename);
  Serial.println(str);

}

} }

//Setups up the software serial, resets OpenLog so we know what state it's in, and waits //for OpenLog to come online and report '<' that it is ready to receive characters to record void setupOpenLog(void) { pinMode(resetOpenLog, OUTPUT); OpenLog.begin(9600);

//Reset OpenLog digitalWrite(resetOpenLog, LOW); delay(100); digitalWrite(resetOpenLog, HIGH);

//Wait for OpenLog to respond with '<' to indicate it is alive and recording to a file while (1) { if (OpenLog.available()) if (OpenLog.read() == '<') break; } }

//This function creates a given file and then opens it in append mode (ready to record characters to the file) //Then returns to listening mode void createFile(String fileName) {

//Old way OpenLog.print("new "); OpenLog.print(fileName); OpenLog.write(13); //This is \r

//New way //OpenLog.print("new "); //OpenLog.println(filename); //regular println works with OpenLog v2.51 and above

//Wait for OpenLog to return to waiting for a command while (1) { if (OpenLog.available()) if (OpenLog.read() == '>') break; }

OpenLog.print("append "); OpenLog.print(fileName); OpenLog.write(13); //This is \r

//Wait for OpenLog to indicate file is open and ready for writing while (1) { if (OpenLog.available()) if (OpenLog.read() == '<') break; }

//OpenLog is now waiting for characters and will record them to the new file }

void writeFileOffset(String filename, int offset) {

OpenLog.print("write "); OpenLog.print(filename); OpenLog.print(" " + String(offset)); OpenLog.write(13); //This is \r

//Wait for OpenLog to indicate file is open and ready for writing while (1) { if (OpenLog.available()) if (OpenLog.read() == '<') break; }

//OpenLog is now waiting for characters and will record them to the new file }

void deleteFile(String fileName) { OpenLog.print("rm "); OpenLog.print(fileName); OpenLog.write(13); //This is \r

while (1) { if (OpenLog.available()) if (OpenLog.read() == '>') break; } }

//Reads the contents of a given file and dumps it to the serial terminal //This function assumes the OpenLog is in command mode String readFile(String fileName) {

//Old way OpenLog.print("read "); OpenLog.print(fileName); OpenLog.write(13); //This is \r

//New way //OpenLog.print("read "); //OpenLog.println(filename); //regular println works with OpenLog v2.51 and above

//The OpenLog echos the commands we send it by default so we have 'read log823.txt\r' sitting //in the RX buffer. Let's try to not print this. while (1) { if (OpenLog.available()) if (OpenLog.read() == '\r') break; }

//This will listen for characters coming from OpenLog and print them to the terminal //This relies heavily on the SoftSerial buffer not overrunning. This will probably not work //above 38400bps. //This loop will stop listening after 1 second of no characters received String fileData = ""; for (int timeOut = 0 ; timeOut < 1000 ; timeOut++) { while (OpenLog.available()) { while (OpenLog.available()) { fileData += (char)OpenLog.read(); // if(openLogResponse.length() > 98) break; }

  timeOut = 0;
}

delay(1);

}

return fileData; //Serial.print(openLogResponse); //Take the string from OpenLog and push it to the Arduino terminal

//This is not perfect. The above loop will print the '.'s from the log file. These are the two escape characters //recorded before the third escape character is seen. //It will also print the '>' character. This is the OpenLog telling us it is done reading the file.

//This function leaves OpenLog in command mode }

//Check the stats of the SD card via 'disk' command //This function assumes the OpenLog is in command mode void readDisk() {

//Old way OpenLog.print("disk"); OpenLog.write(13); //This is \r

//New way //OpenLog.print("read "); //OpenLog.println(filename); //regular println works with OpenLog v2.51 and above

//The OpenLog echos the commands we send it by default so we have 'disk\r' sitting //in the RX buffer. Let's try to not print this. while (1) { if (OpenLog.available()) if (OpenLog.read() == '\r') break; }

//This will listen for characters coming from OpenLog and print them to the terminal //This relies heavily on the SoftSerial buffer not overrunning. This will probably not work //above 38400bps. //This loop will stop listening after 1 second of no characters received String diskData = ""; for (int timeOut = 0 ; timeOut < 1000 ; timeOut++) { while (OpenLog.available()) {

  while (OpenLog.available()) {
    diskData += (char)OpenLog.read();
  }

  timeOut = 0;
}

delay(1);

}

return diskData; // Serial.print(openLogResponse); //Take the string from OpenLog and push it to the Arduino terminal

//This is not perfect. The above loop will print the '.'s from the log file. These are the two escape characters //recorded before the third escape character is seen. //It will also print the '>' character. This is the OpenLog telling us it is done reading the file.

//This function leaves OpenLog in command mode }

//This function pushes OpenLog into command mode void gotoCommandMode(void) { //Send three control z to enter OpenLog command mode //Works with Arduino v1.0 OpenLog.write(26); OpenLog.write(26); OpenLog.write(26);

//Wait for OpenLog to respond with '>' to indicate we are in command mode while (1) { if (OpenLog.available()) if (OpenLog.read() == '>') break; } }

[nseidle]

What version of OpenLog firmware are you using? See the command set. Once the device is in command mode send the ? to get the list of commands and the firmware version.

When I opened the file from the PC and checked the number written I noticed that it was not just "10" but "10���".

The ???s are the escape characters that are sent to the OpenLog to get OpenLog into command mode.

In addition I would like to let you know that the method I have implemented for using the command "write File OFFSET" is not working and I do not know what I have done wrong.

Not sure. I'll try to replicate it.

Finally could you please let me know why each time I create a file I have to use "gotoCommandMode();" since I have declared it in the "setup()"?

I don't understand the question. You don't declare functions in setup(). However, you can run them. gotoCommandMode() is a function to get OpenLog out of logging mode and into Command Mode so that you can do things like create/delete/write to files.

[nseidle]

I have re-written the examples and have written an example demonstrating how to use an offset such as

write fileName.txt 10

Please see example 5.