diff --git a/platform/mcu/MK22FN512xxx12/drivers/rtc.c b/platform/mcu/MK22FN512xxx12/drivers/rtc.c
new file mode 100644
index 00000000..83a78312
--- /dev/null
+++ b/platform/mcu/MK22FN512xxx12/drivers/rtc.c
@@ -0,0 +1,72 @@
+/***************************************************************************
+ *   Copyright (C) 2020 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN                             *
+ *                         Frederik Saraci IU2NRO                          *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#include <os.h>
+#include "rtc.h"
+
+/*
+ * NOTE: even if the MK22FN512 MCU has an RTC, it is unusable in GDx platforms
+ * because they lacks of the proper hardware necessary to run the RTC also when
+ * the MCU is powered off.
+ * We thus provide a stub implementation of the RTC API to avoid cluttering the
+ * main code with #ifdefs checking wheter or not the RTC can be actually used.
+ */
+
+void rtc_init() { }
+
+void rtc_shutdown() { }
+
+void rtc_setTime(curTime_t t)
+{
+    (void) t;
+}
+
+void rtc_setHour(uint8_t hours, uint8_t minutes, uint8_t seconds)
+{
+    (void) hours;
+    (void) minutes;
+    (void) seconds;
+}
+
+void rtc_setDate(uint8_t date, uint8_t month, uint8_t year)
+{
+    (void) date;
+    (void) month;
+    (void) year;
+}
+
+curTime_t rtc_getTime()
+{
+    curTime_t t;
+
+    t.hour   = 12;
+    t.minute = 12;
+    t.second = 12;
+    t.year  = 20;
+    t.day   = 4;
+    t.month = 12;
+    t.date  = 12;
+
+    return t;
+}
+
+void rtc_dstSet() { }
+
+void rtc_dstClear() { }
diff --git a/platform/targets/GD77/hwconfig.h b/platform/targets/GD77/hwconfig.h
index f2cf591c..21c1dee7 100644
--- a/platform/targets/GD77/hwconfig.h
+++ b/platform/targets/GD77/hwconfig.h
@@ -23,10 +23,6 @@
 
 #include "MK22F51212.h"
 
-/* Signalling LEDs */
-#define GREEN_LED  GPIOB,18
-#define RED_LED    GPIOC,14
-
 /* Screen dimensions */
 #define SCREEN_WIDTH 128
 #define SCREEN_HEIGHT 64
@@ -42,6 +38,10 @@
 #define LCD_CLK     GPIOC,11
 #define LCD_DAT     GPIOC,12
 
+/* Signalling LEDs */
+#define GREEN_LED  GPIOB,18
+#define RED_LED    GPIOC,14
+
 /* Keyboard */
 #define KB_ROW0 GPIOB,19
 #define KB_ROW1 GPIOB,20
diff --git a/platform/targets/GD77/platform.c b/platform/targets/GD77/platform.c
index 73ea952b..0b7fda89 100644
--- a/platform/targets/GD77/platform.c
+++ b/platform/targets/GD77/platform.c
@@ -21,35 +21,24 @@
 #include <platform.h>
 #include <gpio.h>
 #include "hwconfig.h"
-#include "rtc.h"
-
-curTime_t rtc_getTime()
-{
-    /* TODO */
-    curTime_t t;
-    t.hour   = 12;
-    t.minute = 12;
-    t.second = 12;
-    t.year  = 20;
-    t.day   = 4;
-    t.month = 12;
-    t.date  = 12;
-    return t;
-}
 
 void platform_init()
 {
     /* Configure GPIOs */
     gpio_setMode(GREEN_LED, OUTPUT);
-    gpio_setMode(RED_LED, OUTPUT);
+    gpio_setMode(RED_LED,   OUTPUT);
 
     gpio_setMode(LCD_BKLIGHT, OUTPUT);
     gpio_clearPin(LCD_BKLIGHT);
+
+    gpio_setMode(PTT_SW, INPUT);
 }
 
 void platform_terminate()
 {
-    /* TODO */
+    gpio_clearPin(LCD_BKLIGHT);
+    gpio_clearPin(RED_LED);
+    gpio_clearPin(GREEN_LED);
 }
 
 float platform_getVbat()
@@ -72,14 +61,14 @@ float platform_getVolumeLevel()
 
 uint8_t platform_getChSelector()
 {
-    /* TODO */
+    /* GD77 does not have a channel selector */
     return 0;
 }
 
 bool platform_getPttStatus()
 {
-    /* TODO */
-    return false;
+    /* PTT line has a pullup resistor with PTT switch closing to ground */
+    return (gpio_readPin(PTT_SW) == 0) ? true : false;
 }
 
 void platform_ledOn(led_t led)
@@ -119,6 +108,7 @@ void platform_ledOff(led_t led)
 void platform_beepStart(uint16_t freq)
 {
     /* TODO */
+
     (void) freq;
 }
 
@@ -129,7 +119,7 @@ void platform_beepStop()
 
 void platform_setBacklightLevel(uint8_t level)
 {
-    /* TODO */
+    /* TODO: backlight dimming */
     if(level > 1)
     {
         gpio_setPin(LCD_BKLIGHT);