TCCR?:
  _modify:
    COM?:
      _write_constraint: enum
    FOC?:
      access: write-only
  COM?:
    _replace_enum:
      DISCONNECTED:  [0, "Normal port operation, OC2 disconnected"]
      MATCH_CLEAR:   [2, "Clear OC2 on Compare Match (If PWM is enabled, OC2 is set at BOTTOM)"]
      MATCH_SET:     [3, "Set OC2 on Compare Match (If PWM is enabled, OC2 is cleared at BOTTOM)"]
  CS?:
    _replace_enum:
      NO_CLOCK:      [0, "No clock source (Timer/Counter stopped)"]
      DIRECT:        [1, "Running, No Prescaling"]
      PRESCALE_8:    [2, "Running, CLK/8"]
      PRESCALE_32:   [3, "Running, CLK/32"]
      PRESCALE_64:   [4, "Running, CLK/64"]
      PRESCALE_128:  [5, "Running, CLK/128"]
      PRESCALE_256:  [6, "Running, CLK/256"]
      PRESCALE_1024: [7, "Running, CLK/1024"]