diff --git a/slides/lectures/resources/gpio_avr/slides.md b/slides/lectures/resources/gpio_avr/slides.md
index 090b6ab29fe255ad5fd7c43d8698c15b109af1cc..f1ee7142aecd08dd181ee2bac7e1aeb3b0e0df63 100644
--- a/slides/lectures/resources/gpio_avr/slides.md
+++ b/slides/lectures/resources/gpio_avr/slides.md
@@ -20,7 +20,7 @@ A simple GPIO
 
 <br>
 
-> <b> DDRx - Data Direction Register. </b> If the data direction bit is 1, the pin is an input. 0 is an output.
+> <b> DDRx - Data Direction Register. </b> If the data direction bit is 0, the pin is an input. 1 is an output.
 
 ```c
 DDRB &= ~(1<<DDB7); // Makes pin PB7 an input