Storing calibration tables on an SD card

Using Arduino Storage
17

Okay, I am really trying here. This goes WAY beyond my understanding of programming. I have zero C++ background and it seems like strtok() is a native C function. This means the examples I can find are near impossible to understand. I have managed to get it to do what seems right (after a ton of trial and error) but it isn’t right.

Here is what I understand my problems to be:

  1. char buf[6]; is a problem. I don’t necessarily know what the length of the calibration value is. Some are like 0.00, some are like ?0.10, and most are like 12.34. I tried char buf[5] but that starting returning gibberish. Basically, I don’t want this at all. I want to retrieve just the chunks in between the commas. I can’t get that to work.

  2. My debug output looks great... but it isn’t inserting the right values into the array. It seems like it is putting the last value into every array element.

  3. Right now, I am swapping variable types just to get the thing to compile. I want to build an array of floats. To get this to work, I can only get chars in there. I don’t seem to be able to parse the serial data for a comma without using chars.

#include <SdFat.h>
#include <SdFatUtil.h>

Sd2Card card;
SdVolume volume;
SdFile root;
SdFile file;

char* responseArray[] = {};

// store error strings in flash to save RAM
#define error(s) error_P(PSTR(s))

void error_P(const char* str) {
  PgmPrint("error: ");
  SerialPrintln_P(str);
  if (card.errorCode()) {
    PgmPrint("SD error: ");
    Serial.print(card.errorCode(), HEX);
    Serial.print(',');
    Serial.println(card.errorData(), HEX);
  }
  while(1);
}

void setup(void) {
  
  Serial.begin(9600);
  Serial.println();
  Serial.println("Type any character to start");
  while (!Serial.available());
  Serial.println();
  
  // initialize the SD card at SPI_HALF_SPEED to avoid bus errors with
  // breadboards.  use SPI_FULL_SPEED for better performance.
  if (!card.init(SPI_HALF_SPEED)) error("card.init failed");
  
  // initialize a FAT volume
  if (!volume.init(&card)) error("volume.init failed");
  
  // open the root directory
  if (!root.openRoot(&volume)) error("openRoot failed");
  
  // open a file
  if (file.open(&root, "CSV.TXT", O_READ)) {
    Serial.println("Opened CSV.TXT");
  }
  
  else{
    error("file.open failed");
  }
  
  int16_t n;
  char* parameter;  
  int parserIteration = 0;
  
  char buf[6]; // THIS IS BASICALLY HARD-CODING. I CAN'T GUARANTEE I KNOW THE LENGTH OF THE VALUES IN THE TXT FILE. 
  
  while ((n = file.read(buf, sizeof(buf))) > 0) 
  {
      Serial.print("Entering ");
      parameter = strtok(buf, ",");        
      Serial.print(parameter);
      Serial.print(" into responseArray[");
      Serial.print(parserIteration);
      Serial.println("]");
      
      responseArray[parserIteration] = parameter; // THESE VALUES ARE GOING INTO THE ARRAY AS CHAR* ... I NEED THEM IN THERE AS FLOATS.
      
      parserIteration++;
        
      while (parameter != NULL)
      {
        parameter = strtok(NULL, ","); // NOT SURE WHAT THIS DOES, BUT IT BREAKS IF I DON'T HAVE IT
      }
  }

  Serial.println("\nDone\n");
  
  Serial.println("Now, test the array...\n");
  
  // AND THIS DOESN'T REALLY WORK AT ALL, DESPITE LOOKING CORRECT IN MY DEBUG OUTPUT
  
  Serial.print("responseArray[0] now = ");
  Serial.println(responseArray[0]);
  Serial.print("responseArray[1] now = ");
  Serial.println(responseArray[1]);
  Serial.print("responseArray[18] now = ");
  Serial.println(responseArray[18]);
}

void loop(void) {}

and my seemingly awesome serial output that does nothing...

Type any character to start

Opened CSV.TXT
Entering 00.00 into responseArray[0]
Entering 00.08 into responseArray[1]
Entering -0.10 into responseArray[2]
Entering 00.56 into responseArray[3]
Entering 01.36 into responseArray[4]
Entering 01.89 into responseArray[5]
Entering 03.15 into responseArray[6]
Entering 03.15 into responseArray[7]
Entering 05.23 into responseArray[8]
Entering 06.20 into responseArray[9]
Entering 07.34 into responseArray[10]
Entering 09.71 into responseArray[11]
Entering 09.29 into responseArray[12]
Entering 10.76 into responseArray[13]
Entering 13.43 into responseArray[14]
Entering 17.42 into responseArray[15]
Entering 16.76 into responseArray[16]
Entering 21.10 into responseArray[17]
Entering 23.51 into responseArray[18]
Entering 26.18 into responseArray[19]
Entering 27.96 into responseArray[20]
Entering 25.20 into responseArray[21]
Entering 25.83 into responseArray[22]
Entering 25.56 into responseArray[23]
Entering 26.84 into responseArray[24]
Entering 28.69 into responseArray[25]
Entering 27.88 into responseArray[26]
Entering 23.08 into responseArray[27]
Entering 25.11 into responseArray[28]
Entering 25.29 into responseArray[29]
Entering 24.52
*@ into responseArray[30]

Done

Now, test the array...

responseArray[0] now = 24.52
*@
responseArray[1] now = 
responseArray[18] now = 24.52
*@

Getting closer!