Hello.
I have been testing my Mega 2560 with a Catalex MicroSD Card Adapter hooked up to the following pins (this information is probably not very useful as I have verified that the SD card works):
5V -> VCC
GND -> GND
SCK -> digital pin 52
MOSI -> digital pin 51
MISO -> digital pin 50
CS -> digital pin 53
I have uploaded CardInfo successfully, to get the usual messages on the serial monitor (I have tweaked the code, changing chipSelect to 53 instead of the usual 10):
Initializing SD card...Wiring is correct and a card is present.
Card type: SDHC
Volume type is FAT32
Volume size (bytes): 4040163328
Volume size (Kbytes): 3945472
Volume size (Mbytes): 3853
Files found on the card (name, date and size in bytes):
SYSTEM~1/ 2018-04-10 20:57:44
INDEXE~1 2018-04-10 20:57:44 76
WPSETT~1.DAT 2018-04-10 21:11:16 12
TEST.TXT 2000-01-01 01:00:00 27
Moreover, I then uploaded ReadWrite (I have modified this program too as before, but also changed the test message to include "你好、こんにちは" ('Hello' in Chinese and Japanese):
This is the code after modification:
/*
SD card read/write
This example shows how to read and write data to and from an SD card file
The circuit:
* SD card attached to SPI bus as follows:
** MOSI - pin 11
** MISO - pin 12
** CLK - pin 13
** CS - pin 53 (for MKRZero SD: SDCARD_SS_PIN)
created Nov 2010
by David A. Mellis
modified 9 Apr 2012
by Tom Igoe
This example code is in the public domain.
*/
#include <SPI.h>
#include <SD.h>
File myFile;
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
Serial.print("Initializing SD card...");
if (!SD.begin(53)) {
Serial.println("initialization failed!");
return;
}
Serial.println("initialization done.");
// open the file. note that only one file can be open at a time,
// so you have to close this one before opening another.
myFile = SD.open("test.txt", FILE_WRITE);
// if the file opened okay, write to it:
if (myFile) {
Serial.print("Writing to test.txt...");
myFile.println("testing 1, 2, 3. 你好、こんにちは");
// close the file:
myFile.close();
Serial.println("done.");
} else {
// if the file didn't open, print an error:
Serial.println("error opening test.txt");
}
// re-open the file for reading:
myFile = SD.open("test.txt");
if (myFile) {
Serial.println("test.txt:");
// read from the file until there's nothing else in it:
while (myFile.available()) {
Serial.write(myFile.read());
}
// close the file:
myFile.close();
} else {
// if the file didn't open, print an error:
Serial.println("error opening test.txt");
}
}
void loop() {
// nothing happens after setup
}
It works the same as before, except now in the serial monitor it outputs this:
Initializing SD card...initialization done.
Writing to test.txt...done.
test.txt:
testing 1, 2, 3. ????????
I know this is not an issue with the serial monitor. The serial monitor that comes with Arduino cannot handle non-ASCII text.
However, the problem lies in what was written to the text file. It has the same text that was in the text file: "testing 1, 2, 3. ????????", even though I had not made the program to write question marks.
My question is: How do I utilise the SD library to write UTF-8?
Sorry if the post was too long. This is my first time writing a post on the forums.
Many thanks.