board_simtrace: Add minimal debug menu on debug USART

firmware/libboard/simtrace/source/board_simtrace.c

@@ -10,8 +10,28 @@
 
 void board_exec_dbg_cmd(int ch)
 {
+	switch (ch) {
+	case '?':
+		printf("\t?\thelp\n\r");
+		printf("\tR\treset SAM3\n\r");
+		break;
+	case 'R':
+		printf("Asking NVIC to reset us\n\r");
+		USBD_Disconnect();
+		NVIC_SystemReset();
+		break;
+	default:
+		printf("Unknown command '%c'\n\r", ch);
+		break;
+	}
 }
 
 void board_main_top(void)
 {
+#ifndef APPLICATION_dfu
+	usb_buf_init();
+
+	/* Initialize checking for card insert/remove events */
+	//card_present_init();
+#endif
 }