diff --git a/uncore/memserdes.scala b/uncore/memserdes.scala
new file mode 100644
index 00000000..e8d99514
--- /dev/null
+++ b/uncore/memserdes.scala
@@ -0,0 +1,159 @@
+package rocket
+
+import Chisel._
+import Node._
+import Constants._
+import scala.math._
+import uncore._
+
+class ioMemSerialized extends Bundle
+{
+  val req = (new FIFOIO) { Bits(width = MEM_BACKUP_WIDTH) }
+  val resp = (new PipeIO) { Bits(width = MEM_BACKUP_WIDTH) }.flip
+}
+
+class MemSerdes extends Component
+{
+  val io = new Bundle {
+    val wide = new ioMem().flip
+    val narrow = new ioMemSerialized
+  }
+  val abits = io.wide.req_cmd.bits.toBits.getWidth
+  val dbits = io.wide.req_data.bits.toBits.getWidth
+  val rbits = io.wide.resp.bits.getWidth
+
+  val out_buf = Reg() { Bits() }
+  val in_buf = Reg() { Bits() }
+
+  val s_idle :: s_read_addr :: s_write_addr :: s_write_idle :: s_write_data :: Nil = Enum(5) { UFix() }
+  val state = Reg(resetVal = s_idle)
+  val send_cnt = Reg(resetVal = UFix(0, log2Up((max(abits, dbits)+MEM_BACKUP_WIDTH-1)/MEM_BACKUP_WIDTH)))
+  val data_send_cnt = Reg(resetVal = UFix(0, log2Up(REFILL_CYCLES)))
+  val adone = io.narrow.req.ready && send_cnt === UFix((abits-1)/MEM_BACKUP_WIDTH)
+  val ddone = io.narrow.req.ready && send_cnt === UFix((dbits-1)/MEM_BACKUP_WIDTH)
+
+  when (io.narrow.req.valid && io.narrow.req.ready) {
+    send_cnt := send_cnt + UFix(1)
+    out_buf := out_buf >> UFix(MEM_BACKUP_WIDTH)
+  }
+  when (io.wide.req_cmd.valid && io.wide.req_cmd.ready) {
+    out_buf := io.wide.req_cmd.bits.toBits
+  }
+  when (io.wide.req_data.valid && io.wide.req_data.ready) {
+    out_buf := io.wide.req_data.bits.toBits
+  }
+
+  io.wide.req_cmd.ready := state === s_idle
+  io.wide.req_data.ready := state === s_write_idle
+  io.narrow.req.valid := state === s_read_addr || state === s_write_addr || state === s_write_data
+  io.narrow.req.bits := out_buf
+
+  when (state === s_idle && io.wide.req_cmd.valid) {
+    state := Mux(io.wide.req_cmd.bits.rw, s_write_addr, s_read_addr)
+  }
+  when (state === s_read_addr && adone) {
+    state := s_idle
+    send_cnt := UFix(0)
+  }
+  when (state === s_write_addr && adone) {
+    state := s_write_idle
+    send_cnt := UFix(0)
+  }
+  when (state === s_write_idle && io.wide.req_data.valid) {
+    state := s_write_data
+  }
+  when (state === s_write_data && ddone) {
+    data_send_cnt := data_send_cnt + UFix(1)
+    state := Mux(data_send_cnt === UFix(REFILL_CYCLES-1), s_idle, s_write_idle)
+    send_cnt := UFix(0)
+  }
+
+  val recv_cnt = Reg(resetVal = UFix(0, log2Up((rbits+MEM_BACKUP_WIDTH-1)/MEM_BACKUP_WIDTH)))
+  val data_recv_cnt = Reg(resetVal = UFix(0, log2Up(REFILL_CYCLES)))
+  val resp_val = Reg(resetVal = Bool(false))
+
+  resp_val := Bool(false)
+  when (io.narrow.resp.valid) {
+    recv_cnt := recv_cnt + UFix(1)
+    when (recv_cnt === UFix((rbits-1)/MEM_BACKUP_WIDTH)) {
+      recv_cnt := UFix(0)
+      data_recv_cnt := data_recv_cnt + UFix(1)
+      resp_val := Bool(true)
+    }
+    in_buf := Cat(io.narrow.resp.bits, in_buf((rbits+MEM_BACKUP_WIDTH-1)/MEM_BACKUP_WIDTH*MEM_BACKUP_WIDTH-1,MEM_BACKUP_WIDTH))
+  }
+
+  io.wide.resp.valid := resp_val
+  io.wide.resp.bits.tag := in_buf(io.wide.resp.bits.tag.width-1,0)
+  io.wide.resp.bits.data := in_buf >> UFix(io.wide.resp.bits.tag.width)
+}
+
+class MemDessert extends Component // test rig side
+{
+  val io = new Bundle {
+    val narrow = new ioMemSerialized().flip
+    val wide = new ioMem
+  }
+  val abits = io.wide.req_cmd.bits.toBits.getWidth
+  val dbits = io.wide.req_data.bits.toBits.getWidth
+  val rbits = io.wide.resp.bits.getWidth
+
+  require(dbits >= abits && rbits >= dbits)
+  val recv_cnt = Reg(resetVal = UFix(0, log2Up((rbits+MEM_BACKUP_WIDTH-1)/MEM_BACKUP_WIDTH)))
+  val data_recv_cnt = Reg(resetVal = UFix(0, log2Up(REFILL_CYCLES)))
+  val adone = io.narrow.req.valid && recv_cnt === UFix((abits-1)/MEM_BACKUP_WIDTH)
+  val ddone = io.narrow.req.valid && recv_cnt === UFix((dbits-1)/MEM_BACKUP_WIDTH)
+  val rdone = io.narrow.resp.valid && recv_cnt === UFix((rbits-1)/MEM_BACKUP_WIDTH)
+
+  val s_cmd_recv :: s_cmd :: s_data_recv :: s_data :: s_reply :: Nil = Enum(5) { UFix() }
+  val state = Reg(resetVal = s_cmd_recv)
+
+  val in_buf = Reg() { Bits() }
+  when (io.narrow.req.valid && io.narrow.req.ready || io.narrow.resp.valid) {
+    recv_cnt := recv_cnt + UFix(1)
+    in_buf := Cat(io.narrow.req.bits, in_buf((rbits+MEM_BACKUP_WIDTH-1)/MEM_BACKUP_WIDTH*MEM_BACKUP_WIDTH-1,MEM_BACKUP_WIDTH))
+  }
+  io.narrow.req.ready := state === s_cmd_recv || state === s_data_recv
+
+  when (state === s_cmd_recv && adone) {
+    state := s_cmd
+    recv_cnt := UFix(0)
+  }
+  when (state === s_cmd && io.wide.req_cmd.ready) {
+    state := Mux(io.wide.req_cmd.bits.rw, s_data_recv, s_reply)
+  }
+  when (state === s_data_recv && ddone) {
+    state := s_data
+    recv_cnt := UFix(0)
+  }
+  when (state === s_data && io.wide.req_data.ready) {
+    state := s_data_recv
+    when (data_recv_cnt === UFix(REFILL_CYCLES-1)) {
+      state := s_cmd_recv
+    }
+    data_recv_cnt := data_recv_cnt + UFix(1)
+  }
+  when (rdone) { // state === s_reply
+    when (data_recv_cnt === UFix(REFILL_CYCLES-1)) {
+      state := s_cmd_recv
+    }
+    recv_cnt := UFix(0)
+    data_recv_cnt := data_recv_cnt + UFix(1)
+  }
+
+  val req_cmd = in_buf >> UFix(((rbits+MEM_BACKUP_WIDTH-1)/MEM_BACKUP_WIDTH - (abits+MEM_BACKUP_WIDTH-1)/MEM_BACKUP_WIDTH)*MEM_BACKUP_WIDTH)
+  io.wide.req_cmd.valid := state === s_cmd
+  io.wide.req_cmd.bits.tag := req_cmd
+  io.wide.req_cmd.bits.addr := req_cmd.toUFix >> UFix(io.wide.req_cmd.bits.tag.width + io.wide.req_cmd.bits.rw.width)
+  io.wide.req_cmd.bits.rw := req_cmd(io.wide.req_cmd.bits.tag.width)
+
+  io.wide.req_data.valid := state === s_data
+  io.wide.req_data.bits.data := in_buf >> UFix(((rbits+MEM_BACKUP_WIDTH-1)/MEM_BACKUP_WIDTH - (dbits+MEM_BACKUP_WIDTH-1)/MEM_BACKUP_WIDTH)*MEM_BACKUP_WIDTH)
+
+  val dataq = (new Queue(REFILL_CYCLES)) { new MemResp }
+  dataq.io.enq <> io.wide.resp
+  dataq.io.deq.ready := recv_cnt === UFix((rbits-1)/MEM_BACKUP_WIDTH)
+
+  io.narrow.resp.valid := dataq.io.deq.valid
+  io.narrow.resp.bits := dataq.io.deq.bits.toBits >> (recv_cnt * UFix(MEM_BACKUP_WIDTH))
+}
diff --git a/uncore/slowio.scala b/uncore/slowio.scala
new file mode 100644
index 00000000..068e90c5
--- /dev/null
+++ b/uncore/slowio.scala
@@ -0,0 +1,50 @@
+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
+}