91 lines
2.1 KiB
Arduino
91 lines
2.1 KiB
Arduino
/*
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SD card read/write
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This example shows how to read and write data to and from an SD card file
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The circuit:
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SD card attached to SPI bus as follows:
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** MISO - pin 4
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** MOSI - pin 7
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** CS - pin 5
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** SCK - pin 6
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created Nov 2010
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by David A. Mellis
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modified 9 Apr 2012
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by Tom Igoe
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This example code is in the public domain.
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*/
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// This are GP pins for SPI0 on the Raspberry Pi Pico board, and connect
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// to different *board* level pinouts. Check the PCB while wiring.
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// Only certain pins can be used by the SPI hardware, so if you change
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// these be sure they are legal or the program will crash.
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// See: https://datasheets.raspberrypi.com/picow/PicoW-A4-Pinout.pdf
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const int _MISO = 4;
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const int _MOSI = 7;
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const int _CS = 5;
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const int _SCK = 6;
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#include <SPI.h>
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#include <SD.h>
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File myFile;
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void setup() {
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// Open serial communications and wait for port to open:
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Serial.begin(115200);
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Serial.print("Initializing SD card...");
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// Ensure the SPI pinout the SD card is connected to is configured properly
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SPI.setRX(_MISO);
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SPI.setTX(_MOSI);
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SPI.setSCK(_SCK);
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if (!SD.begin(_CS)) {
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Serial.println("initialization failed!");
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return;
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}
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Serial.println("initialization done.");
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// open the file. note that only one file can be open at a time,
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// so you have to close this one before opening another.
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myFile = SD.open("test.txt", FILE_WRITE);
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// if the file opened okay, write to it:
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if (myFile) {
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Serial.print("Writing to test.txt...");
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myFile.println("testing 1, 2, 3.");
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// close the file:
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myFile.close();
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Serial.println("done.");
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} else {
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// if the file didn't open, print an error:
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Serial.println("error opening test.txt");
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}
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// re-open the file for reading:
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myFile = SD.open("test.txt");
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if (myFile) {
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Serial.println("test.txt:");
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// read from the file until there's nothing else in it:
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while (myFile.available()) {
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Serial.write(myFile.read());
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}
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// close the file:
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myFile.close();
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} else {
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// if the file didn't open, print an error:
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Serial.println("error opening test.txt");
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}
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}
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void loop() {
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// nothing happens after setup
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}
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