diff --git a/docs/library/pyb.Timer.rst b/docs/library/pyb.Timer.rst
index bb7e7e52d5..532b64da8e 100644
--- a/docs/library/pyb.Timer.rst
+++ b/docs/library/pyb.Timer.rst
@@ -62,7 +62,7 @@ Constructors
 Methods
 -------
 
-.. method:: Timer.init(\*, freq, prescaler, period)
+.. method:: Timer.init(\*, freq, prescaler, period, mode=Timer.UP, div=1, callback=None, deadtime=0)
 
    Initialise the timer.  Initialisation must be either by frequency (in Hz)
    or by prescaler and period::