diff --git a/doc/lab-01_02.typ b/doc/lab-01_02.typ
index 67d226a..d0153d2 100644
--- a/doc/lab-01_02.typ
+++ b/doc/lab-01_02.typ
@@ -331,14 +331,20 @@ for (int i = 0; i < elements; i++) {
       "temperature" = -1991 dot "register value" / 10 + 223000
     $
 
-    The chip ID can be verified in ```/proc/iomem```.
-
-    The register value of the temperature can be verified in the file: ```/sys/class/thermal/thermal_zone0/temp```.
-
+    The chip ID can be verified in ```/proc/iomem```. 
+    The register value of the temperature can be verified in the file: ```/sys/class/thermal/thermal_zone0/temp```. 
     The MAC address can be verified with ``` ifconfig```.
   ]
 )
 
+The resources are savec in a struct: 
+```bash
+static struct resource* resources[3] = {[0] = 0,};
+```
+resources[0] is reserved for the chip ID, resources[1] for the temperature sensor and resources[2] for the Ethernet controller.
+
+
+
 //-------------------
 // Exercise 6: Kernel thread
 //-------------------
diff --git a/src/01-skeleton/skeleton.c b/src/01-skeleton/skeleton.c
index 55d29ed..cdab855 100644
--- a/src/01-skeleton/skeleton.c
+++ b/src/01-skeleton/skeleton.c
@@ -5,37 +5,51 @@
 
 #include <linux/moduleparam.h>	// needed for module parameters
 
-#include <linux/slab.h>
-#include <linux/list.h>
+#include <linux/slab.h> // dynamic memory allocation
+#include <linux/list.h> // linked list
 #include <linux/string.h>
 
+#include <linux/ioport.h>
+#include <linux/io.h>
+
+
 #define TEXT_LENGTH_MAX 255
 
+
 static char* text = "dummy text";
 module_param(text, charp, 0664);
 static int elements = 1;
 module_param(elements, int, 0);
 
+
+// Ex04 - Dynamic memory allocation and linked list
 struct element {
     char text[TEXT_LENGTH_MAX];
-    int unique_number;
+    int32_t unique_number;
     struct list_head node;
 };
 
 static LIST_HEAD (list_unique_elements);
 
+
+// Ex05 - Memory-mapped I/O
+static struct resource* resources[3] = {[0] = 0,};
+
+
 static int __init skeleton_init(void) {
-	pr_info("Linux module skeleton ex04 loaded\n");
+	pr_info("Linux module skeleton ex05 loaded\n");
 	pr_debug("  text: %s\n  elements: %d\n", text, elements);
 	
+
+    // Ex04 - Dynamic memory allocation and linked list
 	struct element* element_ptr = kcalloc(elements, sizeof(struct element), GFP_KERNEL);
 	if (element_ptr == 0) {
 		pr_err("Failed to allocate memory for %d elements\n", elements);
 		return -ENOMEM;
 	}
 	
-	int i;
-	const int length = TEXT_LENGTH_MAX - 1;
+	uint8_t i;
+	const uint8_t length = TEXT_LENGTH_MAX - 1;
 	for (i = 0; i < elements; i++) {
 		struct element* e = element_ptr + i;
         if (e != 0) {
@@ -45,10 +59,75 @@ static int __init skeleton_init(void) {
 			pr_info ("add element %d: %s\n", e->unique_number, e->text);
         }
     }
+
+    // Ex05 - Memory-mapped I/O
+    unsigned char* registers[3] = {[0] = 0,};
+    uint32_t chipid[4] = {[0] = 0,};
+    uint32_t temperature = 0;
+    uint32_t mac_address[2] = {[0] = 0,};
+
+    resources[0] = request_mem_region(0x01c14000, 0x1000, "nanopi - chip ID");
+    resources[1] = request_mem_region(0x01C25000, 0x1000, "nanopi - temperature sensor");
+    resources[2] = request_mem_region(0x01C30000, 0x1000, "nanopi - Ethernet controller");
+    if ((resources[0] == 0) || (resources[1] == 0) || (resources[2] == 0)) {
+        pr_err("Failed to reserve memory region for chip ID, temperature sensor or Ethernet controller\n");
+        return -EFAULT;
+    }
+
+    registers[0] = ioremap(0x01c14000, 0x1000);
+    registers[1] = ioremap(0x01C25000, 0x1000);
+    registers[2] = ioremap(0x01C30000, 0x1000);
+    if (registers[0] == 0) {
+        pr_err("Failed to map processor registers for chip ID\n");
+        return -EFAULT;
+    }
+     if (registers[1] == 0) {
+        pr_err("Failed to map processor registers for temperature sensor\n");
+        return -EFAULT;
+    }
+     if (registers[2] == 0) {
+        pr_err("Failed to map processor registers for Ethernet controller\n");
+        return -EFAULT;
+    }
+
+    chipid[0] = ioread32(registers[0] + 0x200);
+    chipid[1] = ioread32(registers[0] + 0x204);
+    chipid[2] = ioread32(registers[0] + 0x208);
+    chipid[3] = ioread32(registers[0] + 0x20c);
+    pr_info(
+        "chipid=%08x'%08x'%08x'%08x\n",
+        chipid[0], chipid[1], chipid[2], chipid[3]
+    );
+
+    temperature = -1991 * (int32_t) ioread32(registers[1] + 0x80) / 10 + 223000;
+    pr_info(
+        "temperature=%d (register value: %d)\n",
+        temperature, ioread32(registers[1] + 0x80)
+    );
+
+    mac_address[0] = ioread32(registers[2] + 0x50);
+    mac_address[1] = ioread32(registers[2] + 0x54);
+    pr_info(
+        "mac-addr=%02x:%02x:%02x:%02x:%02x:%02x\n",
+        (mac_address[1] >> 0) & 0xff,
+        (mac_address[1] >> 8) & 0xff,
+        (mac_address[1] >> 16) & 0xff,
+        (mac_address[1] >> 24) & 0xff,
+        (mac_address[0] >> 0) & 0xff,
+        (mac_address[0] >> 8) & 0xff
+    );
+
+    iounmap(registers[0]);
+    iounmap(registers[1]);
+    iounmap(registers[2]);
+
+
 	return 0;
 }
 
 static void __exit skeleton_exit(void) {
+
+    // Ex04 - Dynamic memory allocation and linked list
 	struct element* e;
 
     while (!list_empty(&list_unique_elements)) {
@@ -57,6 +136,12 @@ static void __exit skeleton_exit(void) {
         list_del(&e->node);
         kfree(e);
     }
+
+    // Ex05 - Memory-mapped I/O
+    if (resources[0] != 0) release_mem_region(0x01c14000, 0x1000);
+    if (resources[1] != 0) release_mem_region(0x01C25000, 0x1000);
+    if (resources[2] != 0) release_mem_region(0x01C30000, 0x1000);
+
     pr_info ("Linux module skeleton unloaded\n");
 }