using usb as console

apps/chrg/applications/main.c

@@ -3,6 +3,8 @@
 
 #include <board.h>
 #include <drv_gpio.h>
+#include <stdio.h>
+#include <string.h>
 
 #include "shell.h"
 #include "main.h"
@@ -21,6 +23,8 @@ void show_app_version (void)
 
 int main(void)
 {
+	//rt_uint32_t tick = 0;
+
 #if defined(RT_USING_FINSH) && defined(FINSH_USING_MSH)
 	finsh_set_prompt("chrg ");
 #endif
@@ -28,6 +32,8 @@ int main(void)
     while (1) {
         rt_thread_mdelay(1000);
 		chrg_wdt_feed();
+
+		//rt_kprintf("%d\r\n", ++tick);
     }
 }