diff --git a/03_m1284p_WIZNET_loopback_STATIC_IP/Application/loopback/loopback.c b/03_m1284p_WIZNET_loopback_STATIC_IP/Application/loopback/loopback.c
index a921092..8396cf7 100644
--- a/03_m1284p_WIZNET_loopback_STATIC_IP/Application/loopback/loopback.c
+++ b/03_m1284p_WIZNET_loopback_STATIC_IP/Application/loopback/loopback.c
@@ -24,13 +24,13 @@ int32_t loopback_tcps(uint8_t sn, uint8_t* buf, uint16_t port)
 			getSn_DIPR(sn, destip);
 			destport = getSn_DPORT(sn);
 
-			printf("%d:Connected - %d.%d.%d.%d : %d\r\n",sn, destip[0], destip[1], destip[2], destip[3], destport);
+			PRINTF("%d:Connected - %d.%d.%d.%d : %u\r\n",sn, destip[0], destip[1], destip[2], destip[3], destport);
 #endif
 			setSn_IR(sn,Sn_IR_CON);
          }
 		 if((size = getSn_RX_RSR(sn)) > 0) // Don't need to check SOCKERR_BUSY because it doesn't not occur.
          {
-			if(size > DATA_BUF_SIZE) size = DATA_BUF_SIZE;
+			if(size > LOOPBACK_DATA_BUF_SIZE) size = LOOPBACK_DATA_BUF_SIZE;
 			ret = recv(sn, buf, size);
 
 			if(ret <= 0) return ret;      // check SOCKERR_BUSY & SOCKERR_XXX. For showing the occurrence of SOCKERR_BUSY.
@@ -55,12 +55,12 @@ int32_t loopback_tcps(uint8_t sn, uint8_t* buf, uint16_t port)
 #endif
          if((ret = disconnect(sn)) != SOCK_OK) return ret;
 #ifdef _LOOPBACK_DEBUG_
-         printf("%d:Socket Closed\r\n", sn);
+         PRINTF("%d:Socket Closed\r\n", sn);
 #endif
          break;
       case SOCK_INIT :
 #ifdef _LOOPBACK_DEBUG_
-    	 printf("%d:Listen, TCP server loopback, port [%d]\r\n", sn, port);
+    	  PRINTF("%d:Listen, TCP server loopback, port [%u]\r\n", sn, port);
 #endif
          if( (ret = listen(sn)) != SOCK_OK) return ret;
          break;
@@ -102,7 +102,7 @@ int32_t loopback_tcpc(uint8_t sn, uint8_t* buf, uint8_t* destip, uint16_t destpo
          if(getSn_IR(sn) & Sn_IR_CON)	// Socket n interrupt register mask; TCP CON interrupt = connection with peer is successful
          {
 #ifdef _LOOPBACK_DEBUG_
-			printf("%d:Connected to - %d.%d.%d.%d : %d\r\n",sn, destip[0], destip[1], destip[2], destip[3], destport);
+        	 PRINTF("%d:Connected to - %d.%d.%d.%d : %u\r\n",sn, destip[0], destip[1], destip[2], destip[3], destport);
 #endif
 			setSn_IR(sn, Sn_IR_CON);  // this interrupt should be write the bit cleared to '1'
          }
@@ -112,7 +112,7 @@ int32_t loopback_tcpc(uint8_t sn, uint8_t* buf, uint8_t* destip, uint16_t destpo
          //////////////////////////////////////////////////////////////////////////////////////////////
 		 if((size = getSn_RX_RSR(sn)) > 0) // Sn_RX_RSR: Socket n Received Size Register, Receiving data length
          {
-			if(size > DATA_BUF_SIZE) size = DATA_BUF_SIZE; // DATA_BUF_SIZE means user defined buffer size (array)
+			if(size > LOOPBACK_DATA_BUF_SIZE) size = LOOPBACK_DATA_BUF_SIZE; // LOOPBACK_DATA_BUF_SIZE means user defined buffer size (array)
 			ret = recv(sn, buf, size); // Data Receive process (H/W Rx socket buffer -> User's buffer)
 
 			if(ret <= 0) return ret; // If the received data length <= 0, receive failed and process end
@@ -140,13 +140,13 @@ int32_t loopback_tcpc(uint8_t sn, uint8_t* buf, uint8_t* destip, uint16_t destpo
 #endif
          if((ret=disconnect(sn)) != SOCK_OK) return ret;
 #ifdef _LOOPBACK_DEBUG_
-         printf("%d:Socket Closed\r\n", sn);
+         PRINTF("%d:Socket Closed\r\n", sn);
 #endif
          break;
 
       case SOCK_INIT :
 #ifdef _LOOPBACK_DEBUG_
-    	 printf("%d:Try to connect to the %d.%d.%d.%d : %d\r\n", sn, destip[0], destip[1], destip[2], destip[3], destport);
+    	  PRINTF("%d:Try to connect to the %d.%d.%d.%d : %u\r\n", sn, destip[0], destip[1], destip[2], destip[3], destport);
 #endif
     	 if( (ret = connect(sn, destip, destport)) != SOCK_OK) return ret;	//	Try to TCP connect to the TCP server (destination)
          break;
@@ -181,12 +181,12 @@ int32_t loopback_udps(uint8_t sn, uint8_t* buf, uint16_t port)
       case SOCK_UDP :
          if((size = getSn_RX_RSR(sn)) > 0)
          {
-            if(size > DATA_BUF_SIZE) size = DATA_BUF_SIZE;
+            if(size > LOOPBACK_DATA_BUF_SIZE) size = LOOPBACK_DATA_BUF_SIZE;
             ret = recvfrom(sn, buf, size, destip, (uint16_t*)&destport);
             if(ret <= 0)
             {
 #ifdef _LOOPBACK_DEBUG_
-               printf("%d: recvfrom error. %ld\r\n",sn,ret);
+            	PRINTF("%d: recvfrom error. %ld\r\n",sn,ret);
 #endif
                return ret;
             }
@@ -198,7 +198,7 @@ int32_t loopback_udps(uint8_t sn, uint8_t* buf, uint16_t port)
                if(ret < 0)
                {
 #ifdef _LOOPBACK_DEBUG_
-                  printf("%d: sendto error. %ld\r\n",sn,ret);
+            	   PRINTF("%d: sendto error. %ld\r\n",sn,ret);
 #endif
                   return ret;
                }
@@ -213,7 +213,7 @@ int32_t loopback_udps(uint8_t sn, uint8_t* buf, uint16_t port)
          if((ret = socket(sn, Sn_MR_UDP, port, 0x00)) != sn)
             return ret;
 #ifdef _LOOPBACK_DEBUG_
-         printf("%d:Opened, UDP loopback, port [%d]\r\n", sn, port);
+         PRINTF("%d:Opened, UDP loopback, port [%u]\r\n", sn, port);
 #endif
          break;
       default :
diff --git a/03_m1284p_WIZNET_loopback_STATIC_IP/Application/loopback/loopback.h b/03_m1284p_WIZNET_loopback_STATIC_IP/Application/loopback/loopback.h
index 8f5a3d6..5df3cff 100644
--- a/03_m1284p_WIZNET_loopback_STATIC_IP/Application/loopback/loopback.h
+++ b/03_m1284p_WIZNET_loopback_STATIC_IP/Application/loopback/loopback.h
@@ -6,13 +6,15 @@ extern "C" {
 #endif
 
 #include <stdint.h>
+#include <stdio.h>
+#include "../../globals.h"
 
 /* Loopback test debug message printout enable */
 #define	_LOOPBACK_DEBUG_
 
 /* DATA_BUF_SIZE define for Loopback example */
-#ifndef DATA_BUF_SIZE
-	#define DATA_BUF_SIZE			2048
+#ifndef LOOPBACK_DATA_BUF_SIZE
+	#define LOOPBACK_DATA_BUF_SIZE			512
 #endif
 
 /************************/
diff --git a/03_m1284p_WIZNET_loopback_STATIC_IP/globals.h b/03_m1284p_WIZNET_loopback_STATIC_IP/globals.h
index e71ae1d..25410eb 100644
--- a/03_m1284p_WIZNET_loopback_STATIC_IP/globals.h
+++ b/03_m1284p_WIZNET_loopback_STATIC_IP/globals.h
@@ -29,9 +29,11 @@ static FATFS Fatfs;		//File system object for each logical drive. >= 2
 //******************************* Fat FS declare related: END
 
 
-#define HTTPD_MAX_BUF_SIZE	2048 //For Mega1284p(16kb RAM)/Mega2560(8kb RAM)
+//#define HTTPD_MAX_BUF_SIZE	2048 //For Mega1284p(16kb RAM)/Mega2560(8kb RAM)
 //#define HTTPD_MAX_BUF_SIZE	MAX_URI_SIZE+10 //For Mega644p(4kb RAM)/Mega128(4kb RAM) (ie. 512+10=522 bytes look at httpParser.h <_st_http_request> definition)
 
+#define LOOPBACK_DATA_BUF_SIZE 512
+
 #define PRINTF_EN 1
 #if PRINTF_EN
 #define PRINTF(FORMAT,args...) printf_P(PSTR(FORMAT),##args)
@@ -66,4 +68,7 @@ extern const char str_prog_name[] PROGMEM;
 
 extern wiz_NetInfo netInfo;
 
+#define CHK_RAM_LEAKAGE
+#define CHK_UPTIME
+
 #endif /* GLOBALS_H_ */
diff --git a/03_m1284p_WIZNET_loopback_STATIC_IP/main.c b/03_m1284p_WIZNET_loopback_STATIC_IP/main.c
index 690a7b0..931700c 100644
--- a/03_m1284p_WIZNET_loopback_STATIC_IP/main.c
+++ b/03_m1284p_WIZNET_loopback_STATIC_IP/main.c
@@ -210,7 +210,7 @@ uint16_t adc_read(uint8_t channel)
 #define PORT_TCPS		5000
 #define PORT_UDPS       3000
 
-#define ETH_MAX_BUF_SIZE	2048
+#define ETH_MAX_BUF_SIZE	LOOPBACK_DATA_BUF_SIZE
 
 unsigned char ethBuf0[ETH_MAX_BUF_SIZE];
 unsigned char ethBuf1[ETH_MAX_BUF_SIZE];
@@ -329,6 +329,7 @@ int main()
 	/* Loopback Test: TCP Server and UDP */
 	// Test for Ethernet data transfer validation
 	uint32_t timer_link_1sec = millis();
+	uint32_t timer_uptime_60sec = millis();
 	while(1)
 	{
 		//Here at least every 1sec
@@ -358,6 +359,20 @@ int main()
 			}
 		}
 
+		if((millis()-timer_uptime_60sec)> 60000)
+		{
+			//here every 60 sec
+			timer_uptime_60sec = millis();
+#ifdef CHK_RAM_LEAKAGE
+			//Printout RAM usage every 1 minute
+   			PRINTF(">> Free RAM is: %d bytes\r\n", freeRam());
+#endif
+
+#ifdef CHK_UPTIME
+			//Printout RAM usage every 1 minute
+   			PRINTF(">> Uptime %lu sec\r\n", millis()/1000);
+#endif
+		}
 	}
 	return 0;
 }
diff --git a/04_m1284p_WIZNET_loopback_DHCP/main.c b/04_m1284p_WIZNET_loopback_DHCP/main.c
index 8699cdb..21772d8 100644
--- a/04_m1284p_WIZNET_loopback_DHCP/main.c
+++ b/04_m1284p_WIZNET_loopback_DHCP/main.c
@@ -298,8 +298,8 @@ void my_ip_assign(void)
 //   Display_Net_Conf();
 	print_network_information();
 #if 1
-   printf("DHCP LEASED TIME : %ld Sec.\r\n", getDHCPLeasetime());
-   printf("\r\n");
+   PRINTF("DHCP LEASED TIME : %ld Sec.\r\n", getDHCPLeasetime());
+   PRINTF("\r\n");
 #endif
 }
 
@@ -395,6 +395,7 @@ int main()
 				//Every 1min print-out DHCP leased time elapse
 #ifdef _DHCP_LEASED_TIME_DEBUG_
 			   PRINTF("DHCP LEASED TIME elapse: %lu Sec.\r\n", timer_dhcp_1sec_count );
+			   PRINTF("DHCP LEASED TIME : %ld Sec.\r\n", getDHCPLeasetime());
 #endif
 			}
 		}