Revamp VendingMachine.scala as cookbook example

* Move to cookbook
* Change FSM implementation to use switch & is
* Add non-FSM implementation
* Add execution-driven test

1 files changed, 31 insertions, 0 deletions

diff --git a/src/test/scala/examples/ImplicitStateVendingMachine.scala b/src/test/scala/examples/ImplicitStateVendingMachine.scala
new file mode 100644
index 00000000..ae1e28dd
--- /dev/null
+++ b/src/test/scala/examples/ImplicitStateVendingMachine.scala
@@ -0,0 +1,31 @@
+// See LICENSE for license details.
+
+package examples
+
+import chiselTests.ChiselFlatSpec
+import chisel3._
+
+// Vending machine implemented with an implicit state machine
+class ImplicitStateVendingMachine extends SimpleVendingMachine {
+  // We let the value of nickel be 1 and dime be 2 for efficiency reasons
+  val value = Reg(init = 0.asUInt(3.W))
+  val incValue = Wire(init = 0.asUInt(3.W))
+  val doDispense = value >= 4.U // 4 * nickel as 1 == $0.20
+
+  when (doDispense) {
+    value := 0.U // No change given
+  } .otherwise {
+    value := value + incValue
+  }
+
+  when (io.nickel) { incValue := 1.U }
+  when (io.dime) { incValue := 2.U }
+
+  io.dispense := doDispense
+}
+
+class ImplicitStateVendingMachineSpec extends ChiselFlatSpec {
+  "An vending machine implemented with implicit state" should "work" in {
+    assertTesterPasses { new SimpleVendingMachineTester(new ImplicitStateVendingMachine) }
+  }
+}