diff --git a/main.c b/main.c
index 84cba76..ae87bca 100644
--- a/main.c
+++ b/main.c
@@ -312,13 +312,13 @@ static void clock_hours(void)
  */
 static void process_command(char* str)
 {
-/* split command */
+	// split command
 	const char* delimiter = " ";
 	char* word = strtok(str,delimiter);
 	if (!word) {
 		goto error;
 	}
-	/* parse command */
+	// parse command
 	if (0==strcmp(word,"help")) {
 		printf("available commands:\n");
 		printf("time [HH:MM:SS]\n");
@@ -348,7 +348,7 @@ int main(void)
 {	
 	rcc_clock_setup_in_hse_8mhz_out_72mhz(); // use 8 MHz high speed external clock to generate 72 MHz internal clock
     usart_setup(); // setup USART (for printing)
-    cdcacm_setup(); // setup USB CDC ACM (for printing)
+	cdcacm_setup(); // setup USB CDC ACM (for printing)
     setbuf(stdout, NULL); // set standard out buffer to NULL to immediately print   
     setbuf(stderr, NULL); // set standard error buffer to NULL to immediately print
 
@@ -406,7 +406,7 @@ int main(void)
 
 	printf("welcome to the CuVoodoo LED clock\n"); // print welcome message
 	led_on(); // switch on LED to indicate setup completed
-	
+
 	// read internal reference 1.2V and RTC battery voltages
 	uint8_t channels[] = {ADC_CHANNEL17, BATTERY_ADC_CHANNEL}; // voltages to convert
 	adc_set_regular_sequence(ADC1, LENGTH(channels), channels); // set channels to convert
@@ -417,10 +417,14 @@ int main(void)
 	while (!adc_eoc(ADC1)); // wait until conversion finished
 	uint16_t battery_value = adc_read_regular(ADC1); // read converted battery voltage
 	float battery_voltage = battery_value*1.2/ref_value; // calculate battery voltage
-	if (battery_voltage<2.4) {
-		printf("/!\\ low ");
+	if (battery_voltage<1.0) {
+		printf("no battery detected\n");
+	} else {
+		if (battery_voltage<2.4) {
+			printf("/!\\ low ");
+		}
+		printf("battery voltage: %.2fV\n", battery_voltage);
 	}
-	printf("battery voltage: %.2fV\n", battery_voltage);
 	
 	// show voltage on LEDs
 	if (battery_voltage<1.0) { // battery probable not connected
@@ -500,6 +504,7 @@ int main(void)
 				adc_start_conversion_regular(ADC1); // start measuring ambient luminosity
 			}
 			if ((rtc_get_counter_val()%ticks_second)==0) { // one second passed
+				printf("tick: %lu\n", rtc_get_counter_val());
 				led_toggle(); // LED activity to show we are not stuck
 			}
 			if ((rtc_get_counter_val()%ticks_minute)==0) { // one minute passed