diff --git a/C64_4joy_adapter/README.md b/C64_4joy_adapter/README.md
index d6f7e08..5cf3bdc 100644
--- a/C64_4joy_adapter/README.md
+++ b/C64_4joy_adapter/README.md
@@ -3,16 +3,22 @@
 ```
 
 ```
+ cli // 1 clock
  PORTB = *ptr; // is this atomic? probably, because ptr is 6-bit pointer.
  f98:	e0 91 26 01 	lds	r30, 0x0126	; 0x800126 <__data_end> // 2 clocks
  f9c:	f0 91 27 01 	lds	r31, 0x0127	; 0x800127 <__data_end+0x1> // 2 clocks
  fa0:	80 81       	ld	r24, Z // 1 clock
  fa2:	85 b9       	out	0x05, r24	; 5 // 1 clock
+ sei // 1 clock
 ``` 
+500ns
 
 ```
+cli
 mov r31, r1
 mov r30, gpior2
 ld	r24, Z
 out	0x05, r24
+sei
 ``` 
+375ns