diff --git a/Makefile b/Makefile
index d7e3aaa..14a644e 100644
--- a/Makefile
+++ b/Makefile
@@ -60,5 +60,5 @@ ebin:  $(PRG)_eeprom.bin
 	$(OBJCOPY) -j .eeprom --change-section-lma .eeprom=0 -O binary $< $@
 
 install: text
-	uisp -dprog=avr910 -dserial=/dev/ttyS0 -dspeed=115200 -dpart=M8 --erase --upload if=$(PRG).hex
-#	avrdude -p m8 -c butterfly -b 19200 -P /dev/ttyUSB0 -u -e -V -U flash:w:$(PRG).hex
+#	uisp -dprog=avr910 -dserial=/dev/ttyS0 -dspeed=115200 -dpart=M8 --erase --upload if=$(PRG).hex
+	avrdude -p m8 -c butterfly -b 115200 -P /dev/ttyUSB1 -u -e -V -U flash:w:$(PRG).hex
diff --git a/blmc.c b/blmc.c
index d1ee713..03d801c 100644
--- a/blmc.c
+++ b/blmc.c
@@ -122,6 +122,9 @@ void next_phase(void)
 	blmc.rpm_tmp++;
 }
 
+/*
+ * starts motor, must not run from interrupt
+ */
 void spinup(void)
 {
 	uint16_t time = 1000;
@@ -135,18 +138,23 @@ void spinup(void)
 		time -= (time / 24 +1);
 	}
 
+	/* manual spinup complete, analog comperator takes control */
 	blmc.flags = FLAG_PWM_SPINUP | FLAG_COM_NORMAL;
 	next_phase();
 
 	for (time = 0; time < 10; time++)
 		_delay_ms(20);
 
+	/* switch to desired pwm value */
 	blmc.flags = FLAG_PWM_NORMAL | FLAG_COM_NORMAL;
 }
 
+/*
+ * sets new pwm value
+ * called from i2c-slave (set new value) and from timer (recalc current limit)
+ */
 void setpwm(uint8_t pwm)
 {
-
 	if (pwm >= 8) {
 		if (blmc.pwm == 0)
 			blmc.flags = FLAG_PWM_SPINUP | FLAG_COM_SPINUP;
@@ -158,20 +166,24 @@ void setpwm(uint8_t pwm)
 		blmc.pwm = 0;
 	}
 
+	/* do spinup with small pwm */
 	if (blmc.flags & FLAG_PWM_SPINUP)
 		pwm = 0x0f;
 	else
 		pwm = blmc.pwm;
 
+	/* raise current limit, TODO: magic value */
 	if (blmc.current > 120)
 		blmc.pwm_limit++;
 
+	/* lower current limit */
 	else if (blmc.pwm_limit > 0)
 		blmc.pwm_limit--;
 
 	if (blmc.pwm_limit > pwm)
 		blmc.pwm_limit = pwm;
 
+	/* set new value */
 	pwm -= blmc.pwm_limit;
 	OCR1A = pwm;
 	OCR1B = pwm;
@@ -201,8 +213,6 @@ ISR(ADC_vect)
 	if (blmc.flags & FLAG_COM_NORMAL)
 		ACSR |= (1<<ACIE) | (1<<ACI);
 
-	sei();
-
 	if (channel == SENSE_CURRENT) {
 		current_tmp += value;
 		current_cnt++;
diff --git a/main.c b/main.c
index 98f7052..2699eb5 100644
--- a/main.c
+++ b/main.c
@@ -58,6 +58,7 @@ ISR(TIMER0_OVF_vect)
 	if (diff < 0x8 && blmc.flags == (FLAG_PWM_NORMAL | FLAG_COM_NORMAL))
 		blmc.flags = FLAG_PWM_SPINUP | FLAG_COM_SPINUP;
 
+	/* calc rpm every second */
 	timer0_cnt++;
 	if (timer0_cnt == 50) {
 		timer0_cnt = 0;