1 files changed, 13 insertions, 1 deletions
diff --git a/wirish/pwm.h b/wirish/pwm.h
index fe170cd..d0bc9e0 100644
--- a/wirish/pwm.h
+++ b/wirish/pwm.h
@@ -35,8 +35,20 @@
 extern "C"{
 #endif
 
+/**
+ * As a convenience, analogWrite is an alias of pwmWrite to ease
+ * porting Arduino code.  However, period and duty will have to be
+ * recalibrated.
+ */
 #define analogWrite pwmWrite
-void pwmWrite(uint8, uint16);
+
+/**
+ * Set the PWM duty on the given pin.
+ *
+ * User code is expected to determine and honor the maximum value
+ * (based on the configured period).
+ */
+void pwmWrite(uint8 pin, uint16 duty_cycle);
 
 #ifdef __cplusplus
 }