Issue with SD card not logging data

Using Arduino Programming Questions
1

Hey guys, I am working on a frequency counter that measures about 4 fans at once. I have gotten it to print fine using Serial.print but I am having issues when I want to log the same data to an SD card. I suspect that the interrupts are what is causing the SD card error and tried using interrupts() and nointerrupts() but I still get the error. If anyone has suggestions I would appreciate it.

[code]
#include "FS.h"
#include "SD.h"
#include "SPI.h"
const byte        interruptPin = 33;              // Assign the interrupt pin
volatile uint64_t StartValue;                     // First interrupt value
volatile uint64_t PeriodCount;                    // period in counts of 0.000001 of a second
float             Freg;                           // frequency
char              str[21];                        // for printing uint64_t values
bool              flag = true;
volatile uint64_t count;
hw_timer_t * timer = NULL;                        // pointer to a variable of type hw_timer_t
portMUX_TYPE mux = portMUX_INITIALIZER_UNLOCKED;  // synchs between maon cose and interrupt?
String Data;


// Digital Event Interrupt
// Enters on falling edge in this example
//=======================================
void IRAM_ATTR handleInterrupt()
{
  portENTER_CRITICAL_ISR(&mux);
  if (flag == true) {
    uint64_t TempVal = timerRead(timer);        // value of timer at interrupt
    PeriodCount = TempVal - StartValue;         // period count between rising edges in 0.000001 of a second
    StartValue = TempVal;                       // puts latest reading as start for next calculation
    count++;
  }
  portEXIT_CRITICAL_ISR(&mux);
  //detachInterrupt(digitalPinToInterrupt(interruptPin));
}

void IRAM_ATTR onTime()
{
  portENTER_CRITICAL_ISR(&mux);
  flag = true;
  count = 0;
  portEXIT_CRITICAL_ISR(&mux);
}




// Converts unit64_t to char for printing
// Serial.println(uintToStr( num, str ));
//================================================
char * uintToStr( const uint64_t num, char *str )
{
  uint8_t i = 0;
  uint64_t n = num;
  do
    i++;
  while ( n /= 10 );

  str[i] = '\0';
  n = num;

  do
    str[--i] = ( n % 10 ) + '0';
  while ( n /= 10 );

  return str;
}

// SetUp
//======================================
void setup()
{
  Serial.begin(115200);
  if (!SD.begin()) {
    Serial.println("Card Mount Failed");
    return;
  }
  uint8_t cardType = SD.cardType();

  if (cardType == CARD_NONE) {
    Serial.println("No SD card attached");
    return;
  }

  Serial.print("SD Card Type: ");
  if (cardType == CARD_MMC) {
    Serial.println("MMC");
  } else if (cardType == CARD_SD) {
    Serial.println("SDSC");
  } else if (cardType == CARD_SDHC) {
    Serial.println("SDHC");
  } else {
    Serial.println("UNKNOWN");
  }

  uint64_t cardSize = SD.cardSize() / (1024 * 1024);
  Serial.printf("SD Card Size: %lluMB\n", cardSize);
  writeFile(SD, "/test.txt", "Hello ");
  timer = timerBegin(2, 80, true);                                                // this returns a pointer to the hw_timer_t global variable
  // 0 = first timer
  // 80 is prescaler so 80MHZ divided by 80 = 1MHZ signal ie 0.000001 of a second
  // true - counts up
  timerStart(timer);  // starts the timer
  timerAttachInterrupt(timer, &onTime, true);
  timerAlarmWrite(timer, 5000000, true);
  timerAlarmEnable(timer);
  pinMode(interruptPin, INPUT_PULLUP);                                            // sets pin high
  attachInterrupt(digitalPinToInterrupt(interruptPin), handleInterrupt, FALLING); // attaches pin to interrupt on Falling Edge
}

void loop()
{
  portENTER_CRITICAL(&mux);
  if (flag == true && PeriodCount != 0 && count == 2) {
    Freg = 1000000.00 / PeriodCount;                    // PeriodCount in 0.000001 of a second
    Serial.print("Frequency   "); Serial.println(Freg);
    Data = "Frequency: " + String(Freg); + "\n";
    appendFile(SD, "/test.txt", Data.c_str());
    delay(200);
  }
  portEXIT_CRITICAL(&mux);
}
[/code]
2

what's your arduino?

3

My bad, Its actually an esp32 but I am sure the same concept applies.

4

appendFile and writeFile are custom functions you wrote or took from somewhere ?

what error do you get?

5

append and write are functions from the SD example sketch for the esp32. I believe they interact with the FS.h library. The esp32 keeps rebooting before it can store anything to the SD card.

6

And writing to SD works fine with those functions if you don’t have the interrupts going on?

7

Yes they work fine without the interrupts.

8

So if you detach the interrupt during the SD access, would that work?

9

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