ESP32-C3-SD_SPI-Speed-Test.ino

#include <Arduino.h>
#include <HWCDC.h>
#include "math.h"
#include "SPI.h"
HWCDC USBSerial;
SPIClass spi = SPIClass(FSPI);

#include "SdFat.h"

// SD_FAT_TYPE = 0 for SdFat/File as defined in SdFatConfig.h,
// 1 for FAT16/FAT32, 2 for exFAT, 3 for FAT16/FAT32 and exFAT.
#define SD_FAT_TYPE 0
#define SD_CONFIG SdSpiConfig(SD_CS, DEDICATED_SPI, SD_SCK_MHZ(40), &spi)

SdFat sd;
File file;

void testFileIO(SdFat &fs, const char *path, uint32_t buffSize, uint32_t numMB)
{
    if(sd.exists(path))
    {
        sd.remove(path);
    }
    uint8_t *buff = (uint8_t *)malloc(buffSize);
    for(int i=0; i<buffSize; i++)
    {
        buff[i] = 33 + (i%10);
    }
    file.open(path, FILE_WRITE);
    if (file)
    {
        size_t i;
        uint32_t start = millis();
        auto numToWrite = (numMB * 1024 * 1024) / buffSize;
        for (i = 0; i < numToWrite; i++)
        {
        file.write(buff, buffSize);
        yield();
        }
        uint32_t end = millis() - start;
        float kbps = numMB * 1024 * 1024 / end;

        USBSerial.printf("%u MB written using %d byte buffer for %u ms @ %.1f KBps\n", numMB, buffSize, end, kbps);
        file.close();
    }
    else
    {
        USBSerial.println("Failed to open file for writing");
    }

    file.open(path,FILE_READ);
    if (file)
    {
        uint32_t len = file.size();
        size_t flen = len;
        uint32_t start = millis();
        while (len)
        {
        size_t toRead = len;
        if (toRead > buffSize)
        {
            toRead = buffSize;
        }
        file.read(buff, toRead);
        len -= toRead;
        }
        uint32_t end = millis() - start;
        float kbps = numMB * 1024 * 1024 / end;
        USBSerial.printf("%u MB read using %d byte buffer for %u ms @ %.1f KBps\n", flen / 1024 / 1024, buffSize, end, kbps);
        file.close();
    }
    else
    {
        USBSerial.println("Failed to open file for reading");
    }

    delete[] buff;
}
void setup() {
  USBSerial.begin();
  spi.begin(SD_CLK,SD_MISO,SD_MOSI,SD_CS);
  // Wait for USB Serial

  if (!sd.begin(SD_CONFIG)) {
    USBSerial.println("Failed to Mount");
    sd.initErrorHalt();
  }
   for (int i = 0; i <= 7; i++)
  {
    testFileIO(sd, "/test.txt", 512 * pow(2, i), 4);
  }
}
void loop() {}