diff --git a/sound_pwm.cpp b/sound_pwm.cpp
index 7ac2b5f..580d59e 100644
--- a/sound_pwm.cpp
+++ b/sound_pwm.cpp
@@ -43,7 +43,7 @@ void PWM::set_freq(unsigned freq) {
 void PWM::begin(unsigned gpio) {
 }
 
-void PWM::start(unsigned duty) {
+void PWM::set_duty(unsigned duty) {
 }
 
 void PWM::stop() {