diff --git a/APIs_Drivers/AnalogIn_ex_2/main.cpp b/APIs_Drivers/AnalogIn_ex_2/main.cpp
index 5084e11..cd2bdda 100644
--- a/APIs_Drivers/AnalogIn_ex_2/main.cpp
+++ b/APIs_Drivers/AnalogIn_ex_2/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 AnalogIn input(A0);
 
 #define NUM_SAMPLES 1024
@@ -15,7 +17,7 @@ int main()
 
     for (int i = 0; i < NUM_SAMPLES; i++) {
         samples[i] = input.read_u16();
-        ThisThread::sleep_for(1);
+        ThisThread::sleep_for(1ms);
     }
 
     printf("Results:\n");
diff --git a/APIs_Drivers/AnalogIn_ex_3/main.cpp b/APIs_Drivers/AnalogIn_ex_3/main.cpp
index 7cdd2f3..cab4019 100644
--- a/APIs_Drivers/AnalogIn_ex_3/main.cpp
+++ b/APIs_Drivers/AnalogIn_ex_3/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 // Initialize a pins to perform analog input and digital output functions
 AnalogIn   ain(A0);
 DigitalOut dout(LED1);
@@ -24,6 +26,6 @@ int main(void)
         // print the percentage and 16 bit normalized values
         printf("percentage: %3.3f%%\n", ain.read() * 100.0f);
         printf("normalized: 0x%04X \n", ain.read_u16());
-        ThisThread::sleep_for(200);
+        ThisThread::sleep_for(200ms);
     }
 }
diff --git a/APIs_Drivers/AnalogOut_ex_2/main.cpp b/APIs_Drivers/AnalogOut_ex_2/main.cpp
index 836b89e..a0b151a 100644
--- a/APIs_Drivers/AnalogOut_ex_2/main.cpp
+++ b/APIs_Drivers/AnalogOut_ex_2/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 // Initialize a pins to perform analog and digital output functions
 // Adjust analog output pin name to your board spec.
 AnalogOut  aout(A5);
@@ -20,7 +22,7 @@ int main(void)
             printf("aout = %1.2f volts\n", aout.read() * 3.3f);
             // turn on the led if the voltage is greater than 0.5f * VCC
             dout = (aout > 0.5f) ? 1 : 0;
-            ThisThread::sleep_for(1000);
+            ThisThread::sleep_for(1s);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/APIs_Drivers/BusInOut_ex_1/main.cpp b/APIs_Drivers/BusInOut_ex_1/main.cpp
index df1c16d..3e7a6fa 100644
--- a/APIs_Drivers/BusInOut_ex_1/main.cpp
+++ b/APIs_Drivers/BusInOut_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 BusInOut pins(D0, D1, D2); // Change these pins to buttons on your board.
 
 int main()
@@ -12,9 +14,9 @@ int main()
     while (1) {
         pins.output();
         pins = 0x3;
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
         pins.input();
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
         if (pins == 0x6) {
             printf("Hello!\n");
         }
diff --git a/APIs_Drivers/BusIn_ex_1/main.cpp b/APIs_Drivers/BusIn_ex_1/main.cpp
index dead529..677c5f0 100644
--- a/APIs_Drivers/BusIn_ex_1/main.cpp
+++ b/APIs_Drivers/BusIn_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 BusIn nibble(D0, D1, D2, D3); // Change these pins to buttons on your board.
 
 int main()
@@ -48,6 +50,6 @@ int main()
                 printf("0b1111, D3,D2,D1,D0 are high \n\r");
                 break;
         }
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
diff --git a/APIs_Drivers/BusOut_ex_1/main.cpp b/APIs_Drivers/BusOut_ex_1/main.cpp
index a54e956..a27c292 100644
--- a/APIs_Drivers/BusOut_ex_1/main.cpp
+++ b/APIs_Drivers/BusOut_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 BusOut myleds(LED1, LED2, LED3, LED4);
 
 int main()
@@ -12,7 +14,7 @@ int main()
     while (1) {
         for (int i = 0; i < 16; i++) {
             myleds = i;
-            ThisThread::sleep_for(250);
+            ThisThread::sleep_for(250ms);
         }
     }
 }
diff --git a/APIs_Drivers/CAN_ex_1/main.cpp b/APIs_Drivers/CAN_ex_1/main.cpp
index 51ea3ef..a4995c9 100644
--- a/APIs_Drivers/CAN_ex_1/main.cpp
+++ b/APIs_Drivers/CAN_ex_1/main.cpp
@@ -10,6 +10,7 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
 
 Ticker ticker;
 DigitalOut led1(LED1);
@@ -43,7 +44,7 @@ int main()
             printf("Message received: %d\n", msg.data[0]);
             led2 = !led2;
         }
-        ThisThread::sleep_for(200);
+        ThisThread::sleep_for(200ms);
     }
 }
 
diff --git a/APIs_Drivers/DigitalInOut_ex_1/main.cpp b/APIs_Drivers/DigitalInOut_ex_1/main.cpp
index 24d85e2..45a656f 100644
--- a/APIs_Drivers/DigitalInOut_ex_1/main.cpp
+++ b/APIs_Drivers/DigitalInOut_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 DigitalInOut mypin(LED1);
 
 int main()
@@ -21,11 +23,11 @@ int main()
         // write to pin as output
         mypin.output();
         mypin = !mypin; // toggle output
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
 
         // read from pin as input
         mypin.input();
         printf("mypin.read() = %d \n\r", mypin.read());
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
     }
 }
diff --git a/APIs_Drivers/DigitalIn_ex_1/main.cpp b/APIs_Drivers/DigitalIn_ex_1/main.cpp
index e03d6aa..80db9c1 100644
--- a/APIs_Drivers/DigitalIn_ex_1/main.cpp
+++ b/APIs_Drivers/DigitalIn_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 DigitalIn  mypin(SW2); // change this to the button on your board
 DigitalOut myled(LED1);
 
@@ -22,6 +24,6 @@ int main()
     while (1) {
         printf("mypin has value : %d \n\r", mypin.read());
         myled = mypin; // toggle led based on value of button
-        ThisThread::sleep_for(250);
+        ThisThread::sleep_for(250ms);
     }
 }
diff --git a/APIs_Drivers/DigitalOut_ex_1/main.cpp b/APIs_Drivers/DigitalOut_ex_1/main.cpp
index 6ddc38d..e0dd20c 100644
--- a/APIs_Drivers/DigitalOut_ex_1/main.cpp
+++ b/APIs_Drivers/DigitalOut_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 DigitalOut myled(LED1);
 
 int main()
@@ -18,10 +20,10 @@ int main()
     while (1) {
         myled = 1;          // set LED1 pin to high
         printf("myled = %d \n\r", (uint8_t)myled);
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
 
         myled.write(0);     // set LED1 pin to low
         printf("myled = %d \n\r", myled.read());
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
     }
 }
diff --git a/APIs_Drivers/I2C_ex_1/main.cpp b/APIs_Drivers/I2C_ex_1/main.cpp
index f5c2cb5..8729489 100644
--- a/APIs_Drivers/I2C_ex_1/main.cpp
+++ b/APIs_Drivers/I2C_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 // Read temperature from LM75BD
 
 I2C i2c(I2C_SDA, I2C_SCL);
@@ -20,7 +22,7 @@ int main()
         cmd[1] = 0x00;
         i2c.write(addr8bit, cmd, 2);
 
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
 
         cmd[0] = 0x00;
         i2c.write(addr8bit, cmd, 1);
diff --git a/APIs_Drivers/InterruptIn_ex_1/main.cpp b/APIs_Drivers/InterruptIn_ex_1/main.cpp
index 1797ea7..50893a0 100644
--- a/APIs_Drivers/InterruptIn_ex_1/main.cpp
+++ b/APIs_Drivers/InterruptIn_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 class Counter {
 public:
     Counter(PinName pin) : _interrupt(pin)          // create the InterruptIn on the pin specified to Counter
@@ -33,6 +35,6 @@ int main()
 {
     while (1) {
         printf("Count so far: %d\n", counter.read());
-        ThisThread::sleep_for(2000);
+        ThisThread::sleep_for(2s);
     }
 }
diff --git a/APIs_Drivers/InterruptIn_ex_2/main.cpp b/APIs_Drivers/InterruptIn_ex_2/main.cpp
index 1b90ce2..619e6de 100644
--- a/APIs_Drivers/InterruptIn_ex_2/main.cpp
+++ b/APIs_Drivers/InterruptIn_ex_2/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 InterruptIn button(SW2);
 DigitalOut led(LED1);
 DigitalOut flash(LED4);
@@ -19,6 +21,6 @@ int main()
     button.rise(&flip);  // attach the address of the flip function to the rising edge
     while (1) {          // wait around, interrupts will interrupt this!
         flash = !flash;
-        ThisThread::sleep_for(250);
+        ThisThread::sleep_for(250ms);
     }
 }
diff --git a/APIs_Drivers/PortIn_ex_1/main.cpp b/APIs_Drivers/PortIn_ex_1/main.cpp
index 46d9a2c..f302fb3 100644
--- a/APIs_Drivers/PortIn_ex_1/main.cpp
+++ b/APIs_Drivers/PortIn_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 // Toggle all four LEDs
 // LED1 = P1.18  LED2 = P1.20  LED3 = P1.21  LED4 = P1.23
 #define LED_MASK 0x00B40000
@@ -17,8 +19,8 @@ int main()
     ledport.output();
     while (1) {
         ledport = LED_MASK;
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
         ledport = 0;
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
diff --git a/APIs_Drivers/PortOut_ex_1/main.cpp b/APIs_Drivers/PortOut_ex_1/main.cpp
index 8a02e23..c2cefd6 100644
--- a/APIs_Drivers/PortOut_ex_1/main.cpp
+++ b/APIs_Drivers/PortOut_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 // Toggle all four LEDs
 // LED1 = P1.18  LED2 = P1.20  LED3 = P1.21  LED4 = P1.23
 #define LED_MASK 0x00B40000
@@ -15,8 +17,8 @@ int main()
 {
     while (1) {
         ledport = LED_MASK;
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
         ledport = 0;
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
diff --git a/APIs_Drivers/QSPI/main.cpp b/APIs_Drivers/QSPI/main.cpp
index ca322d8..4258813 100644
--- a/APIs_Drivers/QSPI/main.cpp
+++ b/APIs_Drivers/QSPI/main.cpp
@@ -21,6 +21,8 @@
 #include "mbed.h"
 #include "drivers/QSPI.h"
 
+using namespace std::chrono_literals;
+
 // For Nordic platforms, use fast read. The QSPI flash memory start address,
 // along with the total buffer size, needs to be 4-byte aligned, or divisible by 4.
 #if TARGET_NORDIC
@@ -53,7 +55,7 @@ static bool mem_ready()
         if (QSPI_STATUS_OK != qspi_device.command_transfer(CMD_RDSR, -1, NULL, 0, status_value, STATUS_REG_SIZE)) {
             printf("Reading Status Register failed \n");
         }
-        ThisThread::sleep_for(1);
+        ThisThread::sleep_for(1ms);
     } while ((status_value[0] & BIT_WIP) != 0 && retries);
 
     if ((status_value[0] & BIT_WIP) != 0) {
diff --git a/APIs_Drivers/Ticker_Example/main.cpp b/APIs_Drivers/Ticker_Example/main.cpp
index 4a49314..57387c6 100644
--- a/APIs_Drivers/Ticker_Example/main.cpp
+++ b/APIs_Drivers/Ticker_Example/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 // A class for flip()-ing a DigitalOut
 class Flipper {
 public:
@@ -26,11 +28,11 @@ Ticker t;
 int main()
 {
     // the address of the object, member function, and interval
-    t.attach(callback(&f, &Flipper::flip), 2.0);
+    t.attach(callback(&f, &Flipper::flip), 2s);
 
     // spin in a main loop. flipper will interrupt it to call flip
     while (1) {
         led1 = !led1;
-        ThisThread::sleep_for(200);
+        ThisThread::sleep_for(200ms);
     }
 }
diff --git a/APIs_Drivers/Ticker_HelloWorld/main.cpp b/APIs_Drivers/Ticker_HelloWorld/main.cpp
index 8e94c37..7a9e5ae 100644
--- a/APIs_Drivers/Ticker_HelloWorld/main.cpp
+++ b/APIs_Drivers/Ticker_HelloWorld/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 Ticker flipper;
 DigitalOut led1(LED1);
 DigitalOut led2(LED2);
@@ -16,11 +18,11 @@ void flip()
 int main()
 {
     led2 = 1;
-    flipper.attach(&flip, 2.0); // the address of the function to be attached (flip) and the interval (2 seconds)
+    flipper.attach(&flip, 2s); // the address of the function to be attached (flip) and the interval (2 seconds)
 
     // spin in a main loop. flipper will interrupt it to call flip
     while (1) {
         led1 = !led1;
-        ThisThread::sleep_for(200);
+        ThisThread::sleep_for(200ms);
     }
 }
diff --git a/APIs_Drivers/Timeout_Example/main.cpp b/APIs_Drivers/Timeout_Example/main.cpp
index 8a887b2..5fd0a92 100644
--- a/APIs_Drivers/Timeout_Example/main.cpp
+++ b/APIs_Drivers/Timeout_Example/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 // A class for flip()-ing a DigitalOut
 class Flipper {
 public:
@@ -26,11 +28,11 @@ Timeout t;
 int main()
 {
     // the address of the object, member function, and interval
-    t.attach(callback(&f, &Flipper::flip), 2.0);
+    t.attach(callback(&f, &Flipper::flip), 2s);
 
     // spin in a main loop. flipper will interrupt it to call flip
     while (1) {
         led1 = !led1;
-        ThisThread::sleep_for(200);
+        ThisThread::sleep_for(200ms);
     }
 }
diff --git a/APIs_Drivers/Timeout_HelloWorld/main.cpp b/APIs_Drivers/Timeout_HelloWorld/main.cpp
index cf36eb3..ef00078 100644
--- a/APIs_Drivers/Timeout_HelloWorld/main.cpp
+++ b/APIs_Drivers/Timeout_HelloWorld/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 Timeout flipper;
 DigitalOut led1(LED1);
 DigitalOut led2(LED2);
@@ -16,11 +18,11 @@ void flip()
 int main()
 {
     led2 = 1;
-    flipper.attach(&flip, 2.0); // setup flipper to call flip after 2 seconds
+    flipper.attach(&flip, 2s); // setup flipper to call flip after 2 seconds
 
     // spin in a main loop. flipper will interrupt it to call flip
     while (1) {
         led1 = !led1;
-        ThisThread::sleep_for(200);
+        ThisThread::sleep_for(200ms);
     }
 }
diff --git a/APIs_Drivers/Watchdog_ex_1/main.cpp b/APIs_Drivers/Watchdog_ex_1/main.cpp
index 2d7e41f..21cfe60 100644
--- a/APIs_Drivers/Watchdog_ex_1/main.cpp
+++ b/APIs_Drivers/Watchdog_ex_1/main.cpp
@@ -5,9 +5,13 @@
 
 #include "mbed.h"
 
-const uint32_t TIMEOUT_MS = 5000;
+#include <mstd_atomic>
+
+using namespace std::chrono_literals;
+
+const auto TIMEOUT = 5000ms;
 InterruptIn button(BUTTON1);
-volatile int countdown = 9;
+volatile int countdown{9};
 
 void trigger()
 {
@@ -20,7 +24,7 @@ int main()
     printf("\r\nTarget started.\r\n");
 
     Watchdog &watchdog = Watchdog::get_instance();
-    watchdog.start(TIMEOUT_MS);
+    watchdog.start(TIMEOUT.count());
     button.rise(&trigger);
 
     uint32_t watchdog_timeout = watchdog.get_timeout();
@@ -31,6 +35,6 @@ int main()
     while (1) {
         printf("\r%3i", countdown--);
         fflush(stdout);
-        ThisThread::sleep_for(TIMEOUT_MS / 10);
+        ThisThread::sleep_for(TIMEOUT / 10);
     }
 }
diff --git a/APIs_Drivers/lowpowerTicker_ex_1/main.cpp b/APIs_Drivers/lowpowerTicker_ex_1/main.cpp
index 910dfa1..a54904d 100644
--- a/APIs_Drivers/lowpowerTicker_ex_1/main.cpp
+++ b/APIs_Drivers/lowpowerTicker_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 LowPowerTicker flipper;
 DigitalOut led1(LED1);
 
@@ -16,9 +18,9 @@ void flip()
 int main()
 {
     led1 = 1;
-    flipper.attach(&flip, 2.0); // the address of the function to be attached (flip) and the interval (2 seconds)
+    flipper.attach(&flip, 2s); // the address of the function to be attached (flip) and the interval (2 seconds)
 
     while (1) {
-        ThisThread::sleep_for(200);
+        ThisThread::sleep_for(200ms);
     }
 }
diff --git a/APIs_Drivers/lowpowerTimeout_ex_1/main.cpp b/APIs_Drivers/lowpowerTimeout_ex_1/main.cpp
index 499153d..f5acfa6 100644
--- a/APIs_Drivers/lowpowerTimeout_ex_1/main.cpp
+++ b/APIs_Drivers/lowpowerTimeout_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 LowPowerTimeout flipper;
 DigitalOut led1(LED1);
 DigitalOut led2(LED2);
@@ -17,11 +19,11 @@ void flip()
 int main()
 {
     led2 = 1;
-    flipper.attach(&flip, 2.0); // setup flipper to call flip after 2 seconds
+    flipper.attach(&flip, 2s); // setup flipper to call flip after 2 seconds
 
     // spin in a main loop. flipper will interrupt it to call flip
     while (1) {
         led1 = !led1;
-        ThisThread::sleep_for(200);
+        ThisThread::sleep_for(200ms);
     }
 }
diff --git a/APIs_NetworkSocket/TCPSocket_ConnStateCb/main.cpp b/APIs_NetworkSocket/TCPSocket_ConnStateCb/main.cpp
index d34efaf..12e5262 100644
--- a/APIs_NetworkSocket/TCPSocket_ConnStateCb/main.cpp
+++ b/APIs_NetworkSocket/TCPSocket_ConnStateCb/main.cpp
@@ -6,6 +6,8 @@
 #include "mbed.h"
 #include "nsapi_types.h"
 
+using namespace std::chrono_literals;
+
 // Network interface
 EthernetInterface eth;
 Mutex print_mutex;
@@ -50,7 +52,7 @@ int main()
     eth.connect();
 
     safe_print("Connecting started...\r\n");
-    ThisThread::sleep_for(10000);
+    ThisThread::sleep_for(10s);
 
     safe_print("Disconnect\r\n");
     eth.disconnect();
diff --git a/APIs_Platform/DeepSleepLock_Example_1/main.cpp b/APIs_Platform/DeepSleepLock_Example_1/main.cpp
index 2cb86b0..a481bcd 100644
--- a/APIs_Platform/DeepSleepLock_Example_1/main.cpp
+++ b/APIs_Platform/DeepSleepLock_Example_1/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 InterruptIn button(BUTTON1);
 DigitalOut led(LED1);
 
@@ -23,6 +25,6 @@ int main()
 
     while (1) {
         // Wait and let interrupts take care of the rest
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
diff --git a/APIs_Platform/FileHandle_sigio/main.cpp b/APIs_Platform/FileHandle_sigio/main.cpp
index 8ee022a..fd882fa 100644
--- a/APIs_Platform/FileHandle_sigio/main.cpp
+++ b/APIs_Platform/FileHandle_sigio/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 static DigitalOut led1(LED1);
 static DigitalOut led2(LED2);
 
@@ -35,6 +37,6 @@ int main()
 
     while (1) {
         led1 = !led1;
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
     }
 }
diff --git a/APIs_Platform/Memory_tracing_ex_1/main.cpp b/APIs_Platform/Memory_tracing_ex_1/main.cpp
index dbcfaf7..b515cc2 100644
--- a/APIs_Platform/Memory_tracing_ex_1/main.cpp
+++ b/APIs_Platform/Memory_tracing_ex_1/main.cpp
@@ -7,6 +7,7 @@
 #include "mbed.h"
 #include "mbed_mem_trace.h"
 
+using namespace std::chrono_literals;
 
 int main()
 {
@@ -15,7 +16,7 @@ int main()
         void *p = malloc(50);
         printf("50B allocated at %p\n", p);
 
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
 
         free(p);
         printf("50B freed at %p\n\n", p);
diff --git a/APIs_Platform/PlatformMutex_ex_1/main.cpp b/APIs_Platform/PlatformMutex_ex_1/main.cpp
index 606d300..38dca2c 100644
--- a/APIs_Platform/PlatformMutex_ex_1/main.cpp
+++ b/APIs_Platform/PlatformMutex_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 PlatformMutex stdio_mutex;
 Thread t2;
 Thread t3;
@@ -16,20 +18,20 @@ void notify(const char *name, int state)
     stdio_mutex.unlock();
 }
 
-void test_thread(void const *args)
+void test_thread(const char *args)
 {
     while (true) {
-        notify((const char *)args, 0);
-        ThisThread::sleep_for(1000);
-        notify((const char *)args, 1);
-        ThisThread::sleep_for(1000);
+        notify(args, 0);
+        ThisThread::sleep_for(1s);
+        notify(args, 1);
+        ThisThread::sleep_for(1s);
     }
 }
 
 int main()
 {
-    t2.start(callback(test_thread, (void *)"Th 2"));
-    t3.start(callback(test_thread, (void *)"Th 3"));
+    t2.start(callback(test_thread, "Th 2"));
+    t3.start(callback(test_thread, "Th 3"));
 
-    test_thread((void *)"Th 1");
+    test_thread("Th 1");
 }
diff --git a/APIs_Platform/PlatfromOverview_Callbacks/main.cpp b/APIs_Platform/PlatfromOverview_Callbacks/main.cpp
index 6758d58..53b6f37 100644
--- a/APIs_Platform/PlatfromOverview_Callbacks/main.cpp
+++ b/APIs_Platform/PlatfromOverview_Callbacks/main.cpp
@@ -7,14 +7,14 @@
 
 // Create a serial object
 static UnbufferedSerial serial(USBTX, USBRX);
-char *c = new char[1];
 
 // A function that echoes any received data back
 void echo()
 {
     while (serial.readable()) {
-        serial.read(c, sizeof(c));
-        serial.write(c, sizeof(c));
+        char c;
+        serial.read(&c, sizeof(c));
+        serial.write(&c, sizeof(c));
     }
 }
 
diff --git a/APIs_Platform/SleepManager_Example_1/main.cpp b/APIs_Platform/SleepManager_Example_1/main.cpp
index 95570ae..0e595a2 100644
--- a/APIs_Platform/SleepManager_Example_1/main.cpp
+++ b/APIs_Platform/SleepManager_Example_1/main.cpp
@@ -4,12 +4,13 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
 
 int main()
 {
     // Deep sleep for 1 second
     printf("Deep sleep allowed: %i\r\n", sleep_manager_can_deep_sleep());
-    ThisThread::sleep_for(1000);
+    ThisThread::sleep_for(1s);
 
     // Lock deep sleep
     printf("Locking deep sleep\r\n");
@@ -17,5 +18,5 @@ int main()
 
     // Sleep for 1 second
     printf("Deep sleep allowed: %i\r\n", sleep_manager_can_deep_sleep());
-    ThisThread::sleep_for(1000);
+    ThisThread::sleep_for(1s);
 }
diff --git a/APIs_Platform/time_HelloWorld/main.cpp b/APIs_Platform/time_HelloWorld/main.cpp
index c68b87d..90032f1 100644
--- a/APIs_Platform/time_HelloWorld/main.cpp
+++ b/APIs_Platform/time_HelloWorld/main.cpp
@@ -4,6 +4,7 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
 
 int main()
 {
@@ -20,6 +21,6 @@ int main()
         strftime(buffer, 32, "%I:%M %p\n", localtime(&seconds));
         printf("Time as a custom formatted string = %s", buffer);
 
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
diff --git a/APIs_RTOS/Basic/main.cpp b/APIs_RTOS/Basic/main.cpp
index 7359a21..2f40b43 100644
--- a/APIs_RTOS/Basic/main.cpp
+++ b/APIs_RTOS/Basic/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 DigitalOut led1(LED1);
 DigitalOut led2(LED2);
 Thread thread;
@@ -12,7 +14,7 @@ void led2_thread()
 {
     while (true) {
         led2 = !led2;
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
 
@@ -22,6 +24,6 @@ int main()
 
     while (true) {
         led1 = !led1;
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
     }
 }
diff --git a/APIs_RTOS/ConditionVariable_ex_1/main.cpp b/APIs_RTOS/ConditionVariable_ex_1/main.cpp
index d1799af..df807df 100644
--- a/APIs_RTOS/ConditionVariable_ex_1/main.cpp
+++ b/APIs_RTOS/ConditionVariable_ex_1/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 Mutex mutex;
 ConditionVariable cond(mutex);
 
@@ -40,7 +42,7 @@ int main()
         cond.notify_all();
         mutex.unlock();
 
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 
     mutex.lock();
diff --git a/APIs_RTOS/EventFlags/main.cpp b/APIs_RTOS/EventFlags/main.cpp
index 9dfa357..bf0bc72 100644
--- a/APIs_RTOS/EventFlags/main.cpp
+++ b/APIs_RTOS/EventFlags/main.cpp
@@ -1,5 +1,7 @@
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 #define SAMPLE_FLAG1 (1UL << 0)
 #define SAMPLE_FLAG2 (1UL << 9)
 
@@ -21,9 +23,9 @@ int main()
     worker_thread.start(mbed::callback(worker_thread_fun));
 
     while (true) {
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
         event_flags.set(SAMPLE_FLAG1);
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
         event_flags.set(SAMPLE_FLAG2);
     }
 }
diff --git a/APIs_RTOS/Events_ex_1/main.cpp b/APIs_RTOS/Events_ex_1/main.cpp
index 92dba9a..4070177 100644
--- a/APIs_RTOS/Events_ex_1/main.cpp
+++ b/APIs_RTOS/Events_ex_1/main.cpp
@@ -10,7 +10,6 @@ void handler(int count);
 Event<void(int)> event1(&queue, handler);
 Event<void(int)> event2(&queue, handler);
 
-
 void handler(int count)
 {
     unsigned time_ms = equeue_tick();
@@ -25,20 +24,18 @@ void post_events(void)
     // subject to any delay and period specified. Each time an event has
     // been dispatched it will be re-queued ready for the next dispatch
     // period.
-    event1.post(1);      // Event1 with a value of 1
-    event1.post(2);      // Event1 with a value of 2
-    event1.post(3);      // Event1 with a value of 3
+    event1.post(1); // Event1 with a value of 1
+    event1.post(2); // Event1 with a value of 2
+    event1.post(3); // Event1 with a value of 3
 
     // Cancel the last event posted ie Event1 with a value of 3
     event1.cancel();
 
-    event1.post(4);      // Event1 with a value of 4
-
-    event2.post(5);      // Event2 with a value of 5
+    event1.post(4); // Event1 with a value of 4
 
+    event2.post(5); // Event2 with a value of 5
 }
 
-
 // Example  demonstrates the following:
 // 1. Post 5 different events to a queue
 // 2. Configure the event delay and period for each
@@ -83,11 +80,11 @@ int main()
 
     // The event can be manually configured for special timing requirements
     // specified in milliseconds (using Chrono durations)
-    event1.delay(100ms);       // Starting delay - 100 msec
-    event1.period(200ms);      // Delay between each event - 200msec
+    event1.delay(100ms);  // Starting delay - 100 msec
+    event1.period(200ms); // Delay between each event - 200msec
 
-    event2.delay(400ms);           // Starting delay - 400 msec
-    event2.period(non_periodic);   // Single non periodic event
+    event2.delay(400ms);         // Starting delay - 400 msec
+    event2.period(non_periodic); // Single non periodic event
 
     event_thread.start(callback(post_events));
 
@@ -99,5 +96,4 @@ int main()
     queue.dispatch_for(800ms);
 
     event_thread.join();
-
 }
diff --git a/APIs_RTOS/Flags/main.cpp b/APIs_RTOS/Flags/main.cpp
index 90ef977..dfc6e41 100644
--- a/APIs_RTOS/Flags/main.cpp
+++ b/APIs_RTOS/Flags/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 Thread thread;
 DigitalOut led(LED1);
 
@@ -21,7 +23,7 @@ int main(void)
     thread.start(callback(led_thread));
 
     while (true) {
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
         thread.flags_set(0x1);
     }
 }
diff --git a/APIs_RTOS/Isr/main.cpp b/APIs_RTOS/Isr/main.cpp
index becba95..129d6e2 100644
--- a/APIs_RTOS/Isr/main.cpp
+++ b/APIs_RTOS/Isr/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 Ticker ticker;
 Thread thread;
 Queue<const char *, 5> trail;
@@ -36,7 +38,7 @@ void handler()
         print_lock.unlock();
         while (true) {
             trail.put(&(ExecutionMessages[USER]));
-            ThisThread::sleep_for(500);
+            ThisThread::sleep_for(500ms);
         }
     }
 }
diff --git a/APIs_RTOS/Kernel_get_ms_count/main.cpp b/APIs_RTOS/Kernel_get_ms_count/main.cpp
index be851a3..f63185f 100644
--- a/APIs_RTOS/Kernel_get_ms_count/main.cpp
+++ b/APIs_RTOS/Kernel_get_ms_count/main.cpp
@@ -4,18 +4,20 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono;
+
 int main()
 {
     // 64-bit time doesn't wrap for half a billion years, at least
-    uint64_t now = Kernel::get_ms_count();
+    Kernel::Clock::time_point now = Kernel::Clock::now();
 
     // wait a while
-    ThisThread::sleep_for(10);
+    ThisThread::sleep_for(10ms);
 
-    uint64_t later = Kernel::get_ms_count();
+    Kernel::Clock::time_point later = Kernel::Clock::now();
 
     //calculate millisecs elapsed
-    uint64_t elapsed_ms = later - now;
+    milliseconds elapsed_ms = later - now;
 
-    printf("Elapsed ms: %u \r\n", (uint32_t)elapsed_ms);
+    printf("Elapsed ms: %u \r\n", (uint32_t)elapsed_ms.count());
 }
diff --git a/APIs_RTOS/Kernel_hooks/main.cpp b/APIs_RTOS/Kernel_hooks/main.cpp
index 939ab77..6f78d7e 100644
--- a/APIs_RTOS/Kernel_hooks/main.cpp
+++ b/APIs_RTOS/Kernel_hooks/main.cpp
@@ -5,11 +5,13 @@
 #include "mbed.h"
 #include "Kernel.h"
 
+using namespace std::chrono_literals;
+
 /* Entry function for test thread */
 void test_thread(void)
 {
     printf("\ntest thread started");
-    ThisThread::sleep_for(2000);
+    ThisThread::sleep_for(2s);
     printf("\ntest thread exiting");
 }
 
@@ -37,14 +39,14 @@ int main()
     Kernel::attach_thread_terminate_hook(thread_terminate_hook);
     Thread *newThread = new Thread(osPriorityNormal1, 1024, NULL, NULL);
     newThread->start(callback(test_thread));
-    ThisThread::sleep_for(4000);
+    ThisThread::sleep_for(4s);
 
     printf("\n\nattach_idle_hook demo:\n");
     //Attach a hook for idle task
     Kernel::attach_idle_hook(test_idle_hook);
 
     while (1) {
-        ThisThread::sleep_for(3000);
+        ThisThread::sleep_for(3s);
     }
     printf("\n\n");
 }
diff --git a/APIs_RTOS/Mail/main.cpp b/APIs_RTOS/Mail/main.cpp
index 85e6806..d5b6fd4 100644
--- a/APIs_RTOS/Mail/main.cpp
+++ b/APIs_RTOS/Mail/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 /* Mail */
 typedef struct {
     float    voltage; /* AD result of measured voltage */
@@ -24,7 +26,7 @@ void send_thread(void)
         mail->current = (i * 0.1) * 11;
         mail->counter = i;
         mail_box.put(mail);
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
 
diff --git a/APIs_RTOS/Mutex/main.cpp b/APIs_RTOS/Mutex/main.cpp
index 360fa6f..299871e 100644
--- a/APIs_RTOS/Mutex/main.cpp
+++ b/APIs_RTOS/Mutex/main.cpp
@@ -15,20 +15,20 @@ void notify(const char *name, int state)
     stdio_mutex.unlock();
 }
 
-void test_thread(void const *args)
+void test_thread(const char *args)
 {
     while (true) {
-        notify((const char *)args, 0);
-        ThisThread::sleep_for(1000);
-        notify((const char *)args, 1);
-        ThisThread::sleep_for(1000);
+        notify(args, 0);
+        ThisThread::sleep_for(1s);
+        notify(args, 1);
+        ThisThread::sleep_for(1s);
     }
 }
 
 int main()
 {
-    t2.start(callback(test_thread, (void *)"Th 2"));
-    t3.start(callback(test_thread, (void *)"Th 3"));
+    t2.start(callback(test_thread, "Th 2"));
+    t3.start(callback(test_thread, "Th 3"));
 
-    test_thread((void *)"Th 1");
+    test_thread("Th 1");
 }
diff --git a/APIs_RTOS/Queue/main.cpp b/APIs_RTOS/Queue/main.cpp
index 2854275..9aa751f 100644
--- a/APIs_RTOS/Queue/main.cpp
+++ b/APIs_RTOS/Queue/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 typedef struct {
     float    voltage;   /* AD result of measured voltage */
     float    current;   /* AD result of measured current */
@@ -25,7 +27,7 @@ void send_thread(void)
         message->current = (i * 0.1) * 11;
         message->counter = i;
         queue.put(message);
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
 
diff --git a/APIs_RTOS/Semaphore/main.cpp b/APIs_RTOS/Semaphore/main.cpp
index 61c633e..f8ff611 100644
--- a/APIs_RTOS/Semaphore/main.cpp
+++ b/APIs_RTOS/Semaphore/main.cpp
@@ -4,24 +4,26 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 Semaphore one_slot(1);
 Thread t2;
 Thread t3;
 
-void test_thread(void const *name)
+void test_thread(const char *name)
 {
     while (true) {
         one_slot.acquire();
-        printf("%s\n\r", (const char *)name);
-        ThisThread::sleep_for(1000);
+        printf("%s\n\r", name);
+        ThisThread::sleep_for(1s);
         one_slot.release();
     }
 }
 
 int main(void)
 {
-    t2.start(callback(test_thread, (void *)"Th 2"));
-    t3.start(callback(test_thread, (void *)"Th 3"));
+    t2.start(callback(test_thread, "Th 2"));
+    t3.start(callback(test_thread, "Th 3"));
 
-    test_thread((void *)"Th 1");
+    test_thread("Th 1");
 }
diff --git a/APIs_RTOS/Sonar/main.cpp b/APIs_RTOS/Sonar/main.cpp
index 4e50841..cefcc4b 100644
--- a/APIs_RTOS/Sonar/main.cpp
+++ b/APIs_RTOS/Sonar/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono;
+
 /**
  *  Sonar class for the HC-SR04
  */
@@ -13,9 +15,7 @@ class Sonar {
     Timer        timer;
     Timeout      timeout;  // calls a callback once when a timeout expires
     Ticker       ticker;   // calls a callback repeatedly with a timeout
-    int32_t      begin;
-    int32_t      end;
-    float        distance;
+    duration<float, micro> echo_time;
 
 public:
     /**
@@ -27,7 +27,7 @@ class Sonar {
     Sonar(PinName trigger_pin, PinName echo_pin) : trigger(trigger_pin), echo(echo_pin)
     {
         trigger = 0;
-        distance = -1;
+        echo_time = -1us;
 
         echo.rise(callback(this, &Sonar::echo_in));    // Attach handler to the rising interruptIn edge
         echo.fall(callback(this, &Sonar::echo_fall));  // Attach handler to the falling interruptIn edge
@@ -38,7 +38,7 @@ class Sonar {
      */
     void start(void)
     {
-        ticker.attach(callback(this, &Sonar::background_read), 0.01f);
+        ticker.attach(callback(this, &Sonar::background_read), 100ms);
     }
 
     /**
@@ -56,7 +56,6 @@ class Sonar {
     {
         timer.reset();
         timer.start();
-        begin = timer.read_us();
     }
 
     /**
@@ -65,9 +64,8 @@ class Sonar {
      */
     void echo_fall(void)
     {
-        end = timer.read_us();
+        echo_time = timer.elapsed_time();
         timer.stop();
-        distance = end - begin;
     }
 
     /**
@@ -85,7 +83,7 @@ class Sonar {
     void background_read(void)
     {
         trigger = 1;
-        timeout.attach(callback(this, &Sonar::trigger_toggle), 10.0e-6);
+        timeout.attach(callback(this, &Sonar::trigger_toggle), 1us);
     }
 
     /**
@@ -93,7 +91,8 @@ class Sonar {
      */
     float read(void)
     {
-        return distance / 58.0f;
+        const chrono::duration<float, micro> us_per_cm{58.0f};
+        return echo_time / us_per_cm;
     }
 };
 
@@ -106,7 +105,7 @@ int main()
     sonar.start();
 
     while (1) {
-        ThisThread::sleep_for(100);
+        ThisThread::sleep_for(100ms);
         // Periodically print results from sonar object
         printf("%f\r\n", sonar.read());
     }
diff --git a/APIs_RTOS/Threading_with_callback/main.cpp b/APIs_RTOS/Threading_with_callback/main.cpp
index 222b553..e24d97d 100644
--- a/APIs_RTOS/Threading_with_callback/main.cpp
+++ b/APIs_RTOS/Threading_with_callback/main.cpp
@@ -4,6 +4,8 @@
  */
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 Thread thread;
 DigitalOut led1(LED1);
 volatile bool running = true;
@@ -13,7 +15,7 @@ void blink(DigitalOut *led)
 {
     while (running) {
         *led = !*led;
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
 
@@ -21,7 +23,7 @@ void blink(DigitalOut *led)
 int main()
 {
     thread.start(callback(blink, &led1));
-    ThisThread::sleep_for(5000);
+    ThisThread::sleep_for(5s);
     running = false;
     thread.join();
 }
diff --git a/APIs_USB/USBCDC/main.cpp b/APIs_USB/USBCDC/main.cpp
index c633dc6..d4f7f1c 100644
--- a/APIs_USB/USBCDC/main.cpp
+++ b/APIs_USB/USBCDC/main.cpp
@@ -5,6 +5,8 @@
 #include "mbed.h"
 #include "USBCDC.h"
 
+using namespace std::chrono_literals;
+
 USBCDC cdc;
 
 int main(void)
@@ -13,6 +15,6 @@ int main(void)
     while (1) {
         char msg[] = "Hello world\r\n";
         cdc.send((uint8_t *)msg, strlen(msg));
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
diff --git a/APIs_USB/USBCDC_ECM/main.cpp b/APIs_USB/USBCDC_ECM/main.cpp
index c78bdcf..d34c75b 100644
--- a/APIs_USB/USBCDC_ECM/main.cpp
+++ b/APIs_USB/USBCDC_ECM/main.cpp
@@ -5,6 +5,8 @@
 #include "mbed.h"
 #include "USBCDC_ECM.h"
 
+using namespace std::chrono_literals;
+
 /* Ethernet II frame */
 typedef struct {
     uint8_t dst_mac[6];
@@ -25,11 +27,11 @@ USBCDC_ECM ecm;
 int main()
 {
     // Let the USB device to setup
-    ThisThread::sleep_for(10);
+    ThisThread::sleep_for(10ms);
 
     // Send "Hello world" packets in loop
     while (true) {
         ecm.send((uint8_t *)&packet, sizeof(packet));
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
diff --git a/APIs_USB/USBKeyboard/main.cpp b/APIs_USB/USBKeyboard/main.cpp
index 00e0faa..445eac5 100644
--- a/APIs_USB/USBKeyboard/main.cpp
+++ b/APIs_USB/USBKeyboard/main.cpp
@@ -7,10 +7,12 @@
 
 USBKeyboard key;
 
+using namespace std::chrono_literals;
+
 int main(void)
 {
     while (1) {
         key.printf("Hello World\r\n");
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
diff --git a/APIs_USB/USBMIDI/main.cpp b/APIs_USB/USBMIDI/main.cpp
index ded120f..c7cd51f 100644
--- a/APIs_USB/USBMIDI/main.cpp
+++ b/APIs_USB/USBMIDI/main.cpp
@@ -5,6 +5,8 @@
 #include "mbed.h"
 #include "USBMIDI.h"
 
+using namespace std::chrono_literals;
+
 USBMIDI midi;
 
 int main()
@@ -12,9 +14,9 @@ int main()
     while (1) {
         for (int i = 48; i < 83; i++) { // send some messages!
             midi.write(MIDIMessage::NoteOn(i));
-            ThisThread::sleep_for(250);
+            ThisThread::sleep_for(250ms);
             midi.write(MIDIMessage::NoteOff(i));
-            ThisThread::sleep_for(500);
+            ThisThread::sleep_for(500ms);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/APIs_USB/USBMIDI_Take_Me_Out/main.cpp b/APIs_USB/USBMIDI_Take_Me_Out/main.cpp
index 5d797f4..dfea876 100644
--- a/APIs_USB/USBMIDI_Take_Me_Out/main.cpp
+++ b/APIs_USB/USBMIDI_Take_Me_Out/main.cpp
@@ -5,6 +5,8 @@
 #include "mbed.h"
 #include "USBMIDI.h"
 
+using namespace std::chrono_literals;
+
 #define REST -1
 #define C  0
 #define Cs 1
@@ -28,7 +30,7 @@
 #define OCTAVE6  72
 #define OCTAVE7  84
 
-#define WHOLE_NOTE     1150
+#define WHOLE_NOTE     1150ms
 #define HALF_NOTE      (WHOLE_NOTE / 2)
 #define QUARTER_NOTE   (WHOLE_NOTE / 4)
 #define EIGHTH_NOTE    (WHOLE_NOTE / 8)
@@ -39,7 +41,7 @@
 
 USBMIDI midi;
 
-void PlayNote(int note, int octave, uint32_t duration)
+void PlayNote(int note, int octave, chrono::milliseconds duration)
 {
     if (note == REST) {
         ThisThread::sleep_for(duration);
diff --git a/APIs_USB/USBMouseKeyboard/main.cpp b/APIs_USB/USBMouseKeyboard/main.cpp
index 2b91d8b..4e18546 100644
--- a/APIs_USB/USBMouseKeyboard/main.cpp
+++ b/APIs_USB/USBMouseKeyboard/main.cpp
@@ -5,6 +5,8 @@
 #include "mbed.h"
 #include "USBMouseKeyboard.h"
 
+using namespace std::chrono_literals;
+
 //LED1: NUM_LOCK
 //LED2: CAPS_LOCK
 //LED3: SCROLL_LOCK
@@ -32,14 +34,14 @@ int main(void)
         //example of modifier key press
         key_mouse.key_code(KEY_CAPS_LOCK);
         leds = key_mouse.lock_status();
-        ThisThread::sleep_for(50);
+        ThisThread::sleep_for(50ms);
         key_mouse.media_control(KEY_VOLUME_UP);
         key_mouse.key_code(KEY_NUM_LOCK);
         leds = key_mouse.lock_status();
-        ThisThread::sleep_for(50);
+        ThisThread::sleep_for(50ms);
         angle += 10;
         key_mouse.key_code(KEY_SCROLL_LOCK);
         leds = key_mouse.lock_status();
-        ThisThread::sleep_for(50);
+        ThisThread::sleep_for(50ms);
     }
 }
diff --git a/APIs_USB/USBMouse_absolute_pos/main.cpp b/APIs_USB/USBMouse_absolute_pos/main.cpp
index 2764fbb..9c70e2c 100644
--- a/APIs_USB/USBMouse_absolute_pos/main.cpp
+++ b/APIs_USB/USBMouse_absolute_pos/main.cpp
@@ -5,6 +5,8 @@
 #include "mbed.h"
 #include "USBMouse.h"
 
+using namespace std::chrono_literals;
+
 //setup mouse to be absolute
 USBMouse mouse(true, ABS_MOUSE);
 
@@ -29,6 +31,6 @@ int main(void)
         //x_screen, y_screen will be the mouse's position on the screen
         mouse.move(x_screen, y_screen);
         angle += 3;
-        ThisThread::sleep_for(10);
+        ThisThread::sleep_for(10ms);
     }
-}
\ No newline at end of file
+}
diff --git a/APIs_USB/USBMouse_joystick/main.cpp b/APIs_USB/USBMouse_joystick/main.cpp
index 75fa762..d178af4 100644
--- a/APIs_USB/USBMouse_joystick/main.cpp
+++ b/APIs_USB/USBMouse_joystick/main.cpp
@@ -5,6 +5,8 @@
 #include "mbed.h"
 #include "USBMouse.h"
 
+using namespace std::chrono_literals;
+
 USBMouse mouse;
 // x and y axis of the joystick
 AnalogIn   ainx(A0);
@@ -55,10 +57,10 @@ int main()
         if (a_iny == 99) {
             //click
             mouse.click(MOUSE_LEFT);
-            ThisThread::sleep_for(400);
+            ThisThread::sleep_for(400ms);
         }
         // moves mouse to specified x, y coordinates on screen
         mouse.move(x, y);
-        ThisThread::sleep_for(1);
+        ThisThread::sleep_for(1ms);
     }
 }
diff --git a/APIs_USB/USBMouse_relative_pos/main.cpp b/APIs_USB/USBMouse_relative_pos/main.cpp
index 26663c1..dac1db4 100644
--- a/APIs_USB/USBMouse_relative_pos/main.cpp
+++ b/APIs_USB/USBMouse_relative_pos/main.cpp
@@ -5,6 +5,8 @@
 #include "mbed.h"
 #include "USBMouse.h"
 
+using namespace std::chrono_literals;
+
 //create mouse object
 USBMouse mouse;
 
@@ -23,6 +25,6 @@ int main()
         //will move mouse x, y away from its previous position on the screen
         mouse.move(x, y);
         angle += 3;
-        ThisThread::sleep_for(10);
+        ThisThread::sleep_for(10ms);
     }
 }
diff --git a/APIs_USB/USBSerial/main.cpp b/APIs_USB/USBSerial/main.cpp
index 00759b5..5aefffb 100644
--- a/APIs_USB/USBSerial/main.cpp
+++ b/APIs_USB/USBSerial/main.cpp
@@ -5,6 +5,8 @@
 #include "mbed.h"
 #include "USBSerial.h"
 
+using namespace std::chrono_literals;
+
 //Virtual serial port over USB
 USBSerial serial;
 
@@ -12,6 +14,6 @@ int main(void)
 {
     while (1) {
         serial.printf("I am a virtual serial port\r\n");
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
diff --git a/Tutorials_Debugging/DebugPrintf_BlinksLED/main.cpp b/Tutorials_Debugging/DebugPrintf_BlinksLED/main.cpp
index 58845f8..50a40e8 100644
--- a/Tutorials_Debugging/DebugPrintf_BlinksLED/main.cpp
+++ b/Tutorials_Debugging/DebugPrintf_BlinksLED/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 DigitalOut led1(LED1);
 
 int main()
@@ -14,6 +16,6 @@ int main()
 
         // Print something over the serial connection
         printf("Blink! LED is now %d\r\n", led1.read());
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
     }
 }
diff --git a/Tutorials_Overview/IdleLoop/main.cpp b/Tutorials_Overview/IdleLoop/main.cpp
index 1189147..0b166a7 100644
--- a/Tutorials_Overview/IdleLoop/main.cpp
+++ b/Tutorials_Overview/IdleLoop/main.cpp
@@ -1,6 +1,8 @@
 #include "mbed.h"
 #include "rtos_idle.h"
 
+using namespace std::chrono_literals;
+
 // LED for main thread
 DigitalOut led2(LED2);
 // LED for idle thread
@@ -29,6 +31,6 @@ int main()
 {
 
     watchdogThread.start(callback(&watchdogQueue, &EventQueue::dispatch_forever));
-    watchdogTicker.attach(callback(&watchdogRefreshIsr), 5);
+    watchdogTicker.attach(callback(&watchdogRefreshIsr), 5s);
     rtos_attach_idle_hook(&new_idle_loop);
 }
diff --git a/Tutorials_SerialComm/Serial_ReadToBuffer/main.cpp b/Tutorials_SerialComm/Serial_ReadToBuffer/main.cpp
index 9cb2ab1..367b178 100644
--- a/Tutorials_SerialComm/Serial_ReadToBuffer/main.cpp
+++ b/Tutorials_SerialComm/Serial_ReadToBuffer/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 // Create a serial object
 static BufferedSerial pc(USBTX, USBRX);
 
@@ -13,9 +15,9 @@ int main(void)
     char buffer[10] = {};
     while (1) {
         if (pc.readable()) {
-            ThisThread::sleep_for(100);
+            ThisThread::sleep_for(100ms);
             pc.read(buffer, 10);
             printf("I got '%s'\n", buffer);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/Tutorials_UsingAPIs/Alarm/main.cpp b/Tutorials_UsingAPIs/Alarm/main.cpp
index 4e6b177..b43e8aa 100644
--- a/Tutorials_UsingAPIs/Alarm/main.cpp
+++ b/Tutorials_UsingAPIs/Alarm/main.cpp
@@ -4,25 +4,21 @@
  */
 #include "mbed.h"
 
-// Time constants in seconds
-#define HOUR   60 * 60
-#define MINUTE 60
-
 // Globals
 DigitalOut alarm_out(D2, 0);
-DigitalOut alarm_led(LED_RED, 1);
-DigitalOut hour_led(LED_GREEN, 1);
-DigitalOut min_led(LED_BLUE, 1);
+DigitalOut alarm_led(LED1, 1);
+DigitalOut hour_led(LED2, 1);
+DigitalOut min_led(LED3, 1);
 
 InterruptIn inc_time(BUTTON1);
 InterruptIn sel(BUTTON2);
 
 LowPowerTicker alarm_event;
 
-volatile uint64_t delay        = 0;
-volatile uint8_t  hour_count   = 0;
-volatile uint8_t  min_count    = 0;
-volatile uint8_t  select_state = 0;
+std::chrono::hours hour_inc;
+std::chrono::minutes min_inc;
+
+volatile uint8_t select_state = 0;
 
 // Timer Callbacks
 void inc_select(void)
@@ -48,12 +44,10 @@ void set_time_leds(void)
 void inc_delay(void)
 {
     if (select_state == 0) {
-        delay += HOUR;
-        hour_count++;
+        hour_inc++;
         hour_led = !hour_led;
     } else {
-        delay += MINUTE;
-        min_count++;
+        min_inc++;
         min_led = !min_led;
     }
 }
@@ -92,22 +86,23 @@ int main()
 
     // Sleep while waiting for user input to set the desired delay
     while (select_state < 2) {
-        ThisThread::sleep_for(10);
+        ThisThread::sleep_for(10ms);
     }
 
     // Once the delay has been input, blink back the configured hours and
     // minutes selected
-    for (uint8_t i = 0; i < hour_count * 2; i++) {
+    for (uint8_t i = 0; i < hour_inc.count() * 2; i++) {
         hour_led = !hour_led;
-        ThisThread::sleep_for(250);
+        ThisThread::sleep_for(250ms);
     }
 
-    for (uint8_t i = 0; i < min_count * 2; i++) {
+    for (uint8_t i = 0; i < min_inc.count() * 2; i++) {
         min_led = !min_led;
-        ThisThread::sleep_for(250);
+        ThisThread::sleep_for(250ms);
     }
 
     // Attach the low power ticker with the configured alarm delay
+    auto delay = hour_inc + min_inc;
     alarm_event.attach(&trigger_alarm_out, delay);
 
     // Sleep in the main thread
diff --git a/Tutorials_UsingAPIs/Flow-Control-Active-Polling-Button/main.cpp b/Tutorials_UsingAPIs/Flow-Control-Active-Polling-Button/main.cpp
index e0b578f..6ade906 100644
--- a/Tutorials_UsingAPIs/Flow-Control-Active-Polling-Button/main.cpp
+++ b/Tutorials_UsingAPIs/Flow-Control-Active-Polling-Button/main.cpp
@@ -10,7 +10,7 @@ int main()
     while (1) {
         if (BUTTON_PRESS == button) {
             led = !led;
-            ThisThread::sleep_for(1000);
+            ThisThread::sleep_for(1s);
         }
     }
 }
diff --git a/Tutorials_UsingAPIs/Flow-Control-EventQueue/main.cpp b/Tutorials_UsingAPIs/Flow-Control-EventQueue/main.cpp
index 910b13a..1b28850 100644
--- a/Tutorials_UsingAPIs/Flow-Control-EventQueue/main.cpp
+++ b/Tutorials_UsingAPIs/Flow-Control-EventQueue/main.cpp
@@ -5,6 +5,8 @@
 
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 void flip(DigitalOut &led)
 {
     led = !led;
@@ -19,8 +21,8 @@ int main()
     EventQueue queue;
 
     // events are simple callbacks
-    queue.call_every(1000, flip, led1);
-    queue.call_every(500, flip, led2);
+    queue.call_every(1s, flip, led1);
+    queue.call_every(500ms, flip, led2);
 
     // events are executed by the dispatch method
     queue.dispatch_forever();
diff --git a/Tutorials_UsingAPIs/Flow-Control-Interrupt-Button/main.cpp b/Tutorials_UsingAPIs/Flow-Control-Interrupt-Button/main.cpp
index 7d51d9e..f3c1df6 100644
--- a/Tutorials_UsingAPIs/Flow-Control-Interrupt-Button/main.cpp
+++ b/Tutorials_UsingAPIs/Flow-Control-Interrupt-Button/main.cpp
@@ -1,5 +1,7 @@
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 InterruptIn button(BUTTON1);
 DigitalOut led(LED1);
 DigitalOut heartbeat(LED2);
@@ -14,6 +16,6 @@ int main()
     button.rise(&toggle);  // call toggle function on the rising edge
     while (1) {            // wait around, interrupts will interrupt this!
         heartbeat = !heartbeat;
-        ThisThread::sleep_for(250);
+        ThisThread::sleep_for(250ms);
     }
 }
diff --git a/Tutorials_UsingAPIs/Flow-Control-Thread/main.cpp b/Tutorials_UsingAPIs/Flow-Control-Thread/main.cpp
index e6ab1fb..ecdb35a 100644
--- a/Tutorials_UsingAPIs/Flow-Control-Thread/main.cpp
+++ b/Tutorials_UsingAPIs/Flow-Control-Thread/main.cpp
@@ -1,5 +1,7 @@
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 DigitalOut led1(LED1);
 DigitalOut led2(LED2);
 Thread thread;
@@ -8,7 +10,7 @@ void led2_thread()
 {
     while (true) {
         led2 = !led2;
-        ThisThread::sleep_for(1000);
+        ThisThread::sleep_for(1s);
     }
 }
 
@@ -20,6 +22,6 @@ int main()
 
     while (true) {
         led1 = !led1;
-        ThisThread::sleep_for(500);
+        ThisThread::sleep_for(500ms);
     }
 }
diff --git a/Tutorials_UsingAPIs/Flow-Control-Ticker/main.cpp b/Tutorials_UsingAPIs/Flow-Control-Ticker/main.cpp
index 2e9e21a..f35ed69 100644
--- a/Tutorials_UsingAPIs/Flow-Control-Ticker/main.cpp
+++ b/Tutorials_UsingAPIs/Flow-Control-Ticker/main.cpp
@@ -1,5 +1,7 @@
 #include "mbed.h"
 
+using namespace std::chrono_literals;
+
 Ticker flipper;
 DigitalOut led1(LED1);
 DigitalOut led2(LED2);
@@ -12,11 +14,11 @@ void flip()
 int main()
 {
     led2 = 1;
-    flipper.attach(&flip, 2.0); // call flip function every 2 seconds
+    flipper.attach(&flip, 2s); // call flip function every 2 seconds
 
     // spin in a main loop. flipper will interrupt it to call flip
     while (1) {
         led1 = !led1;
-        ThisThread::sleep_for(200);
+        ThisThread::sleep_for(200ms);
     }
 }