Merge pull request #2588 from adafruit/metro_rp2040_sd

Adding arduino Metro RP2040 SD card example

Author: TheKitty

Adafruit_Metro_RP2040/Arduino/Metro_RP2040_SD_Card_Test/.feather_rp2040.test.only

@@ -0,0 +1,87 @@
+// SPDX-FileCopyrightText: 2023 Liz Clark for Adafruit Industries
+//
+// SPDX-License-Identifier: MIT
+/*
+  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 SPI0 bus as follows:
+ ** MOSI - pin 19
+ ** MISO - pin 20
+ ** CLK - pin 18
+
+ created   Nov 2010
+ by David A. Mellis
+ modified 9 Apr 2012
+ by Tom Igoe
+ modified 14 Feb 2023
+ by Liz Clark
+
+ This example code is in the public domain.
+
+ */
+
+#include "SdFat.h"
+SdFat sd;
+
+#define SD_FAT_TYPE 1
+
+// default CS pin is 23 for Metro RP2040
+#define SD_CS_PIN 23
+
+File32 myFile;
+
+void setup() {
+  // Open serial communications and wait for port to open:
+  Serial.begin(115200);
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for native USB port only
+  }
+
+
+  Serial.print("Initializing SD card...");
+
+  if (!sd.begin(SD_CS_PIN)) {
+    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.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.");
+    myFile.println("hello metro rp2040!");
+    // 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.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
+}