Merge pull request #57 from ucb-ucie/scrambler

Scrambler Module

src/main/scala/Scrambler.scala

@@ -0,0 +1,65 @@
+package edu.berkeley.cs.ucie.digital
+package interfaces
+
+import chisel3._
+import chisel3.util.random._
+
+class Scrambler(
+    afeParams: AfeParams,
+    width: Int,
+    seed: BigInt,
+) extends Module {
+  val io = IO(new Bundle {
+    val data_in = Input(UInt(afeParams.mbSerializerRatio.W))
+    val valid = Input(Bool())
+    val seed = Input(UInt(23.W))
+    val data_out = Output(UInt(afeParams.mbSerializerRatio.W))
+  })
+  val LFSR = Module(
+    new FibonacciLFSR(
+      23,
+      Set(23, 21, 18, 15, 7, 2, 1),
+      Some(seed),
+      XOR,
+      width,
+      false,
+    ),
+  )
+  LFSR.io.increment := io.valid
+  LFSR.io.seed.bits := VecInit(io.seed.asBools)
+  LFSR.io.seed.valid := (reset.asBool)
+  io.data_out := LFSR.io.out.asUInt ^ io.data_in
+}
+
+class UCIeScrambler(
+    afeParams: AfeParams,
+    width: Int,
+    numLanes: Int,
+) extends Module {
+  val io = IO(new Bundle {
+    val data_in = Input(Vec(numLanes, UInt(afeParams.mbSerializerRatio.W)))
+    val valid = Input(Bool())
+    val data_out = Output(Vec(numLanes, UInt(afeParams.mbSerializerRatio.W)))
+  })
+  val UCIe_seeds = List(
+    "1dbfbc",
+    "0607bb",
+    "1ec760",
+    "18c0db",
+    "010f12",
+    "19cfc9",
+    "0277ce",
+    "1bb807",
+  )
+  val seeds = (for (i <- 0 until numLanes) yield UCIe_seeds(i % 8)).toList
+  val scramblers =
+    seeds.map(seed => Module(new Scrambler(afeParams, width, BigInt(seed, 16))))
+  for (i <- 0 until scramblers.length) {
+    scramblers(i).io.data_in := io.data_in(i)
+    scramblers(i).io.valid := io.valid
+    scramblers(i).reset := reset
+    scramblers(i).clock := clock
+    scramblers(i).io.seed := ("h" + seeds(i)).U(23.W)
+    io.data_out(i) := scramblers(i).io.data_out
+  }
+}

src/test/scala/Scrambler.scala

@@ -0,0 +1,40 @@
+package edu.berkeley.cs.ucie.digital
+package interfaces
+
+import chisel3._
+import chiseltest._
+import org.scalatest.funspec.AnyFunSpec
+
+class ScramblerTest extends AnyFunSpec with ChiselScalatestTester {
+
+  describe("Scrambler") {
+    it("4 lane scrambler test") {
+      test(new UCIeScrambler(new AfeParams(), 16, 4)) { c =>
+        c.reset.poke(true.B)
+        c.clock.step()
+        c.clock.step()
+        c.reset.poke(false.B)
+        c.clock.step()
+        c.io.valid.poke(true.B)
+
+        c.io.data_in(0).poke(1.U(16.W))
+        c.io.data_in(1).poke(1012.U(16.W))
+        c.io.data_in(2).poke(823.U(16.W))
+        c.io.data_in(3).poke(134.U(16.W))
+        c.io.data_out(0).expect(49085.U(16.W))
+        c.io.data_out(1).expect(1103.U(16.W))
+        c.io.data_out(2).expect(50263.U(16.W))
+        c.io.data_out(3).expect(49245.U(16.W))
+        c.clock.step()
+        c.io.data_in(0).poke(203.U(16.W))
+        c.io.data_in(1).poke(176.U(16.W))
+        c.io.data_in(2).poke(21.U(16.W))
+        c.io.data_in(3).poke(5847.U(16.W))
+        c.io.data_out(0).expect(65321.U(16.W))
+        c.io.data_out(1).expect(56489.U(16.W))
+        c.io.data_out(2).expect(11245.U(16.W))
+        c.io.data_out(3).expect(57654.U(16.W))
+      }
+    }
+  }
+}