diff --git a/main.c b/main.c
index 021ba08..abd4442 100644
--- a/main.c
+++ b/main.c
@@ -42,6 +42,7 @@
 #include "global.h" // board definitions
 #include "usart.h" // USART utilities
 #include "usb_cdcacm.h" // USB CDC ACM utilities
+#include "led_tm1637.h" // TM1637 7-segment controller utilities
 
 #define WATCHDOG_PERIOD 10000 /**< watchdog period in ms */
 
@@ -183,12 +184,35 @@ void main(void)
 	uint32_t ticks_time = rtc_get_counter_val(); // get time from internal RTC (since first start/power up)
 	printf("uptime: %lu.%02lu:%02lu:%02lu\n", ticks_time/(60*60*24), (ticks_time/(60*60))%24, (ticks_time%(60*60))/60, (ticks_time%60)); // display uptime
 
+	// setup TM1637
+	printf("setup 7-segment display: ");
+	led_tm1637_setup();
+	if (!led_tm1637_time(88,88)) { // test display
+		fprintf(stderr,"could not send time to TM1637\n");
+	}
+	if (!led_tm1637_on()) { // switch on display
+		fprintf(stderr,"could not switch on TM1637\n");
+	}
+	for (uint32_t i=0; i<5000000; i++) { // wait a bit to have the user check the display
+		__asm__("nop");
+	}
+	if (!led_tm1637_text("    ")) { // clear display
+		fprintf(stderr,"could not clear\n");
+	}
+	if (!led_tm1637_off()) { // switch off display
+		fprintf(stderr,"could not switch off TM1637\n");
+	}
+	printf("OK\n");
+	
 	// main loop
 	printf("command input: ready\n");
 	bool action = false; // if an action has been performed don't go to sleep
 	button_flag = false; // reset button flag
 	char c = '\0'; // to store received character
 	bool char_flag = false; // a new character has been received
+	if (!led_tm1637_on()) { // switch on display
+		fprintf(stderr,"could not switch on TM1637\n");
+	}
 	while (true) { // infinite loop
 		iwdg_reset(); // kick the dog
 		while (usart_received) { // data received over UART
@@ -237,6 +261,9 @@ void main(void)
 			if ((ticks_time%(60))==0) { // one minute passed
 				printf("uptime: %lu.%02lu:%02lu:%02lu\n", ticks_time/(60*60*24), (ticks_time/(60*60))%24, (ticks_time%(60*60))/60, (ticks_time%60)); // display uptime
 			}
+			if (!led_tm1637_time((ticks_time%(60*60))/60, ticks_time%60)) {
+				fprintf(stderr,"could not set time on TM1637\n");
+			}
 		}
 		if (action) { // go to sleep if nothing had to be done, else recheck for activity
 			action = false;