Diff: main.cpp

Revision:

1:d65338ce2e7c

Parent:

0:b0a3ecd53c7d

Child:

2:1c1602268656

diff -r b0a3ecd53c7d -r d65338ce2e7c main.cpp
--- a/main.cpp	Mon Mar 21 08:58:22 2016 +0000
+++ b/main.cpp	Wed Aug 23 03:11:41 2017 +0000
@@ -1,46 +1,40 @@
 #include "mbed.h"
 #include "SDFileSystem.h"
 
-DigitalIn btn(USER_BUTTON);
-
-// trim '\n'
-void ntrim(char *str)
-{
-    int i;
-    for (i = 0; str[i] != 0; ++i);
-
-    if (i > 0 && str[i - 1] == '\n')
-        str[i - 1] = 0;
-}
+// mosi, miso, sclk, name
+SDFileSystem sd(PB_15, PB_14, PB_13, PA_9, "sd"); 
 
 int main()
 {
-    // SD filesystem
-    SDFileSystem *sd = new SDFileSystem(PB_15, PB_14, PB_13, PA_9, "sd", NC, SDFileSystem::SWITCH_NONE, 20000000); // mosi, miso, sclk, name, card detect, sw type, freq
-
-    while (1)
-    {
-        if (btn) continue;
+    // 读文件例子
+    FILE *fp = fopen("/sd/test.txt", "r"); //打开文件，路径以“/sd/”开头
 
-        // file open
-        FILE *fp = fopen("/sd/test.txt", "r");
-        if (fp == NULL)
-        {
-            printf("open error!!\r\n");
-            while(1);
-        }
-        
-        // read text file
-        char buf[1024];
-        while (fgets(buf, sizeof(buf), fp) != NULL)
-        {
-            ntrim(buf);            
-            printf("%s\r\n", buf);
-        }
+    if (fp == NULL) //打开失败，原因可能是文件不存在，或卡没有连接好
+    {
+        printf("open error!!\r\n");
+        return 1;
+    }
+    printf("file opened for read\r\n");
+    char buf[64];
+    while (fgets(buf, sizeof(buf), fp) != NULL) //读入一行的C函数
+    {    
+        printf("read '%s'\r\n", buf);
+    }
+    fclose(fp);  //关闭文件，释放资源
+    
+    //printf("card type is 0x%x\r\n" , sd.card_type());
     
-        // file close
-        fclose(fp);        
+    // 写文件例子
+    FILE *fp2 = fopen("/sd/write.txt", "w");
+    if (fp2 == NULL)
+    {
+        printf("open error2!!\r\n");
+        return 1;
+    }
+    printf("file opened for write\r\n");
+    fprintf(fp2, "hello\r\n");
+    fprintf(fp2, "%d", 23333);
+    fclose(fp2);  //写完文件要记得关闭，不然可能没保存上
 
-        wait(1);
-    }
+    return 0;
 }