from machine import pin
from time import sleep_ms
step=pin(3,pin OUT)
dir=pin(2,pin OUT)
  step.value(0)
while(1):
dir.value(1)  
for x in range(200)
  step.value(0)
  step.value(1)
  sleep_ms(5)
dir.value(0)  
for x in range(200)
  step.value(0)
  step.value(1)
  sleep_ms(2)