Achronix Speedster22i Interlaken - Manual (Page 10)

Typical Operation
The IIPC can be used in a variety of applications, and provides the user all of the flexibility
offered by the Interlaken Protocol. The IIPC handles all protocol-related functions needed to
communicate to another device’s Interlaken interface. All handshaking, synchronizing and error
checking are handled by the IIPC. The LBUS is designed to match commonly used packet bus
protocols made common by the SPI4.2 protocol; a detailed description is given in the
User
Interfaces
section.
User’s Task:
• Provide packet data via the Local Bus (LBUS) TX interface, and receive packet data from
the LBUS RX interface.
Flow Control
Flow control information is automatically extracted by the RX path of the IIPC and presented to
the user. Also, the IIPC’s TX path consists of a single pipeline with a single memory buffer.
User’s Tasks:
1. Build the scheduling mechanism external to the IIPC to mux data from different logical
channels.
2. Monitor the flow control information and ensure proper data transmission through the
IIPC
Start-Up Procedure
The following lists the different operation steps upon IIPC power-up:
1. After the device is powered up and the reset procedure completed, the IIPC TX path
starts transmitting Control/Idle words in order to align and synchronize the receiving
device’s Interlaken interface. Similarly, the IIPC RX path listens for Control/Idle words
and goes through its own synchronization procedure.
2. User’s Task: Set all of the flow control input to the IIPC TX path to the XOFF state to
prevent any real data transfer.
3. The RX path will eventually get aligned and synchronized and signal the user logic that
synchronization is complete.
4. User’s Task: Turn the flow control information from XOFF to XON for any of the
channels that are ready to accept data.
5. Similarly when the other device is ready to receive data, it will send XON information to
the IIPC which in turn will tell the user logic which channels can be used to transmit data
on.
The above list describes a simple and easily-implementable procedure by which to initially
configure the IIPC. The user needs to build a scheduler only to mux data amongst the different
logical channels, and use the flow control information output by the IIPC to manage the
UG032, May 15, 2014 10