# Creating the NoC Configuration

The created NoC configuration will be: **3 × 2**

```
0———1
|   |     
2———3
|   |
4———5
|   |
6———7
```

## Steps to Create the NoC

### Step 1: Switch to the branch
- Switch to the branch `tutorial-asplos-2023`:
  ```bash
  git checkout tutorial-asplos-2023
  ```
- **Note**: Source the environment setup script:
  ```bash
  source env.sh
  ```
- It is recommended to build a new Chipyard with Gemmini in the `tutorial-asplos-2023` branch.

---

### Step 2: Edit the Configuration File
- Edit the file located at:
  ```
  chipyard/generators/chipyard/src/main/scala/config/TutorialConfigs.scala
  ```
- Add the following configuration under **`TutorialPhase9Config3dgemmini`**:

```scala
class TutorialPhase9Config3dgemmini extends Config(
  new constellation.soc.WithSbusNoC(constellation.protocol.TLNoCParams(
    constellation.protocol.DiplomaticNetworkNodeMapping(
      // inNodeMappings map master agents onto the NoC
      inNodeMapping = ListMap(
        "Core 0" -> 0,  // Rocket frontend + Gemmini
        "Core 1" -> 1,  // Rocket frontend + Gemmini
        "Core 2" -> 2,  // Rocket frontend + Gemmini
        "serial-tl" -> 0),
      // outNodeMappings map client agents (L2 banks) onto the NoC
      outNodeMapping = ListMap(
        "system[0]" -> 3, "system[1]" -> 4, "system[2]" -> 5, "system[3]" -> 6,
        "pbus" -> 7)),
    NoCParams(
      topology        = TerminalRouter(BidirectionalTorus2D(4, 2)),
      channelParamGen = (a, b) => UserChannelParams(Seq.fill(8) { UserVirtualChannelParams(4) }),
      routingRelation = BlockingVirtualSubnetworksRouting(TerminalRouterRouting(Mesh2DEscapeRouting()), 5, 1),
      skipValidationChecks = true
    )
  )) ++
  // ==========================================
  // DO NOT change below this line without    |
  // carefully adjusting the NoC config above |
  // ==========================================

  // add LeanGemmini to Rocket-core (as frontend)
  new chipyard.config.WithMultiRoCC ++
  new chipyard.config.WithMultiRoCCFromBuildRoCC(0,1,2) ++
  new gemmini.DefaultGemminiConfig(gemmini.GemminiConfigs.leanConfig.copy(use_dedicated_tl_port=false)) ++

  // Add 1 simple RocketCore+gemmini tile
  new freechips.rocketchip.subsystem.WithNBigCores(1) ++
  new freechips.rocketchip.subsystem.WithNBigCores(1) ++
  new freechips.rocketchip.subsystem.WithNBigCores(1) ++

  // Use 4 banks of L2 cache
  new freechips.rocketchip.subsystem.WithNBanks(4) ++

  new chipyard.config.AbstractConfig
)
```

---

### Step 3: Build the Configuration
- Navigate to the directory:
  ```
  chipyard/sims/verilator
  ```
- Build the configuration using the following command:
  ```bash
  make debug CONFIG=TutorialPhase9Config3dgemmini -j10
  ```

---

### Step 4: Check the RTL Files
- Verify the generated RTL files at:
  ```
  chipyard.TestHarness.TutorialPhase9Config3dgemmini/gen-collateral
  ```

---

### Step 5: Edit the Run Script
- Navigate to:
  ```
  chipyard/generators/gemmini
  ```
- Edit the script `scripts/run-verilator.sh`. Replace the existing binary with:
  ```bash
  ./simulator-chipyard-TutorialPhase9Config3dgemmini${DEBUG} $PK ${full_binary_path}
  ```

---

### Step 6: Run the Script
- Run the Verilator simulation with:
  ```bash
  ./scripts/run-verilator.sh —debug template
  ```

---

### Step 7: Analyze the Waveform
- The waveform file `waveform.vcd` will be generated at:
  ```
  chipyard/generators/gemmini/waveforms
  ```
- Open the waveform file using **GTKWave** for analysis.

---