jim hamblen / Mbed OS SD_Card_HelloWorld_Ver5

SD card file helloworld demo using new mbed RTOS ver 5 file driver setup. Pins setup for LPC1768 - read comment in code about project's json file requirements for adding the SD filesystem driver

SD card r/w demo for mbed OS version 5 on LPC1768.

File drivers are added in json file with "target.components_add": ["SD"] for use in most recent OS 5 version.

Test messages are sent to serial port with printf's.

Diff: main.cpp

Revision:
1:3a59eb72e0cf
Parent:
0:3588d7473dce
Child:
2:21d14147254e
--- a/main.cpp	Wed Sep 11 12:39:11 2019 +0000
+++ b/main.cpp	Tue Sep 24 17:32:01 2019 +0000
@@ -1,19 +1,37 @@
 #include "mbed.h"
-// Need "target.components_add": ["SD"] in json project file!
+// NOTE: Need "target.components_add": ["SD"] in json project file!
+// This adds the filesystem driver below for SD cards in a project
 #include "SDBlockDevice.h"
 #include "FATFileSystem.h"
-
+Serial pc(USBTX,USBRX); //change for your mbed serial port
 SDBlockDevice sd(p5, p6, p7, p8);
 FATFileSystem fs("SD");
- 
-int main() {
+char filereadchar=0;
+
+int main()
+{
     sd.init();
     fs.mount(&sd);
- 
-    FILE* fd = fopen("/SD/hi.txt", "w");
-    fprintf(fd, "hello!\n\r");
-    fclose(fd);
- 
+// open and write a message in a new file
+    FILE* fw = fopen("/SD/hi.txt", "w");
+    if(fw == NULL) {
+        error("Could not open new file for write\n\r");
+    }
+    printf("Writing to SD file: hello SD Card!\n\r");
+    fprintf(fw, "hello SD card!\n\r");
+    fclose(fw);
+    printf("\nFile closed for write\n\n\r");
+// open and read back file characters to serial for test
+    FILE* fr = fopen("/SD/hi.txt", "r");
+    if(fr == NULL) {
+        error("Could not open new file for read\n\r");
+    }
+    printf("Reading back from new file: ");
+    while(fscanf(fr,"%c",&filereadchar) == 1) {
+        printf("\%s",&filereadchar);
+    }
+    fclose(fr);
     sd.deinit();
     fs.unmount();
+    printf("\nSD demo complete\n\r");
 }
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