package rocket import Chisel._ import Constants._ class slowIO[T <: Data](val divisor: Int, hold_cycles_in: Int = -1)(data: => T) extends Component { val io = new Bundle { val out_fast = new FIFOIO()(data).flip val out_slow = new FIFOIO()(data) val in_fast = new FIFOIO()(data) val in_slow = new FIFOIO()(data).flip val clk_slow = Bool(OUTPUT) } val hold_cycles = if (hold_cycles_in == -1) divisor/4 else hold_cycles_in require((divisor & (divisor-1)) == 0) require(hold_cycles < divisor/2 && hold_cycles >= 1) val cnt = Reg() { UFix(width = log2Up(divisor)) } cnt := cnt + UFix(1) val out_en = cnt === UFix(divisor/2+hold_cycles-1) // rising edge + hold time val in_en = cnt === UFix(divisor/2-1) // rising edge val in_slow_rdy = Reg(resetVal = Bool(false)) val out_slow_val = Reg(resetVal = Bool(false)) val out_slow_bits = Reg() { data } val fromhost_q = new Queue(1)(data) fromhost_q.io.enq.valid := in_en && (io.in_slow.valid && in_slow_rdy || reset) fromhost_q.io.enq.bits := io.in_slow.bits fromhost_q.io.deq <> io.in_fast val tohost_q = new Queue(1)(data) tohost_q.io.enq <> io.out_fast tohost_q.io.deq.ready := in_en && io.out_slow.ready && out_slow_val when (out_en) { in_slow_rdy := fromhost_q.io.enq.ready out_slow_val := tohost_q.io.deq.valid out_slow_bits := Mux(reset, fromhost_q.io.deq.bits, tohost_q.io.deq.bits) } io.in_slow.ready := in_slow_rdy io.out_slow.valid := out_slow_val io.out_slow.bits := out_slow_bits io.clk_slow := cnt(log2Up(divisor)-1).toBool }