Connections¶

Connections define the physical links between the components of the network (Endpoints and Routers). They determine the topology of the NoC. FlooGen allows for flexible connection schemes, supporting point-to-point links as well as range-based connections for arrays of components.

Configuration¶

Connections are defined under the connections list in the configuration file.

`ConnectionDesc` ¶

Connection class to describe a connection between routers and endpoints.

Attributes:

Name	Type	Description
`src`	`str`	Name of the source component (Endpoint or Router).
`dst`	`str`	Name of the destination component (Endpoint or Router).
`bidirectional`	`Optional[bool]`	If true, creates a full-duplex link (Request and Response channels). Currently, only bidirectional links are supported.
`dst_dir`	`Optional[int]`	Specifies the port direction on the destination router (e.g., `"North"`, `"Local"`, `"Eject"`).
`src_range`	`Optional[List[Tuple[int, int]]]`	Selects a range of indices from the source array to connect. Format: `[(start, end)]` or `[(start_x, end_x), (start_y, end_y)]`.
`dst_range`	`Optional[List[Tuple[int, int]]]`	Selects a range of indices from the destination array to connect.
`src_idx`	`Optional[List[int]]`	Selects specific indices from the source array.
`dst_idx`	`Optional[List[int]]`	Selects specific indices from the destination array.
`allow_multi`	`Optional[bool]`	Allows multiple connections to/from the same port (useful for complex topologies).
`description`	`Optional[str]`	Optional description of the connection.

Examples¶

Basic Connection¶

Connects a single endpoint to a router. This is the most common connection type for simple star or mesh topologies where auto_connect handles the inter-router links.

connections:
  - src: "cpu_0"
    dst: "router_0"

Range Connection (Arrays)¶

When connecting arrays (e.g., a cluster of CPUs to a mesh of routers), you can use src_range and dst_range. This avoids writing a separate connection for every single element.

The following example connects a 4x4 endpoint array (cluster) to a 4x4 router array (router). It maps cluster[0..3][0..3] to router[0..3][0..3].

connections:
  - src: "cluster"
    dst: "router"
    src_range:
      - [0, 3] # X range
      - [0, 3] # Y range
    dst_range:
      - [0, 3]
      - [0, 3]

Specifying Router Ports¶

When manually connecting routers (or specific endpoints), you might need to specify which port direction to attach to. Available directions are usually North, East, South, West, or Eject (Local).

connections:
  - src: "hbm_controller"
    dst: "router_0"
    dst_dir: "West" # Connects HBM to the West port of router_0

Complex Mappings¶

You can map different ranges to specific ports. For example, connecting a linear array of HBM controllers to the bottom edge of a mesh router grid.

connections:
  - src: "hbm"       # Array of 4 HBM endpoints
    dst: "router"    # 4x4 Router mesh
    src_range:
      - [0, 3]       # Select all 4 HBMs
    dst_range:
      - [0, 3]       # Select X indices 0-3
      - [0, 0]       # Select Y index 0 (Bottom row)
    dst_dir: "South" # Connect to the South port of the routers