GPIOA/start
  GPIOA/counter = 1
GPIOA/end
GPIOB/start
  GPIOB/counter = 2
GPIOB/end
GPIOA/start
  GPIOA/counter = 3
GPIOA/end
GPIOB/start
  GPIOB/counter = 4
GPIOB/end
GPIOA/start
  GPIOA/counter = 5