diff --git a/main.c b/main.c
index 14dba91..9394e5a 100644
--- a/main.c
+++ b/main.c
@@ -27,7 +27,8 @@
 #include <libopencm3/cm3/scb.h> // vector table definition
 #include <libopencmsis/core_cm3.h> // Cortex M3 utilities
 
-#include <libopencm3/stm32/spi.h> // SPI library
+#include <libopencm3/stm32/timer.h>
+#include <libopencm3/cm3/nvic.h>
 
 /* own libraries */
 #include "main.h" // board definitions
@@ -64,6 +65,31 @@ static void gpio_setup(void)
 	gpio_set_mode(LED_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, LED_PIN); // set LED pin to 'output push-pull'	
 }
 
+static void timer_setup(void)
+{
+#define VFD_TIMER TIM2
+#define VFD_TIMER_RCC RCC_TIM2
+#define VFD_TIMER_IRQ NVIC_TIM2_IRQ
+
+	rcc_periph_clock_enable(VFD_TIMER_RCC); // enable clock for timer block
+	timer_reset(VFD_TIMER); // reset timer state
+	timer_set_mode(VFD_TIMER, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock,edge alignment (simple count), and count up
+	timer_set_prescaler(VFD_TIMER, (SYSTEM_CLOCK_FREQ/(1<<16))-1); // set the prescaler so this 16 bits timer overflows at 1Hz
+	//timer_set_period(0xffff/(VFD_DIGITS+VFD_MATRIX)/150); // set the refresh frequency
+	timer_set_period(VFD_TIMER, 0xffff);
+	timer_enable_irq(VFD_TIMER, TIM_DIER_CC1IE); // enable interrupt for timer
+	nvic_enable_irq(VFD_TIMER_IRQ); // allow interrupt for timer
+	timer_enable_counter(VFD_TIMER); // enable timer
+}
+
+void tim2_isr(void)
+{
+	if (timer_get_flag(VFD_TIMER, TIM_SR_UIF)) {
+		timer_clear_flag(VFD_TIMER, TIM_SR_UIF);
+		gpio_toggle(LED_PORT, LED_PIN);
+	}
+}
+
 int main(void)
 {	
 	SCB_VTOR = (uint32_t) 0x08002000; // relocate vector table because of the bootloader
@@ -73,6 +99,7 @@ int main(void)
 	usart_setup(); // setup USART (for printing)
 	cdcacm_setup(); // setup USB CDC ACM (for printing)	
 	vfd_setup(); // setup VFD
+	timer_setup();
 	
 	setbuf(stdout, NULL); // set standard out buffer to NULL to immediately print	
 	setbuf(stderr, NULL); // set standard error buffer to NULL to immediately print
diff --git a/main.h b/main.h
index 6d2e1eb..a3d44ab 100644
--- a/main.h
+++ b/main.h
@@ -14,6 +14,9 @@
  */
 /* Copyright (c) 2016 King Kévin <kingkevin@cuvoodoo.info> */
 
+/* system clock frequency in Hz */
+#define SYSTEM_CLOCK_FREQ 72000000
+
 /* LED is on pin 11/PA1 */
 #define LED_RCC RCC_GPIOA
 #define LED_PORT GPIOA