diff --git a/README.md b/README.md
index 4d80def..990cdaf 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,13 @@
 # stepper
 
-stepper motor control via RPi
\ No newline at end of file
+stepper motor control via RPi
+
+## A4988 driver wiring
+GND     3-5.5V ground                   DIRECTION   -> pi gpio
+VDD     3-5.5V logic power supply       STEP
+1B      stepper coil 1                  SLEEP       --l
+1A      stepper coil 1                  RESET       --l
+2A      stepper coil 2                  MS3         -> pi gpio
+2B      stepper coil 2                  MS2         -> pi gpio
+GND     8-35V ground                    MS1         -> pi gpio
+VMOT    8-35V stepper power supply      ENABLE      -> pi gpio