Cyclone V Device Handbook: Volume 2: Transceivers

ID 683586
Date 10/24/2018
Public
Document Table of Contents

1.4. Channel Bonding

The high-speed serial clock and low-speed parallel clock skew between channels and unequal latency in the transmitter phase compensation FIFO contribute to transmitter channel-to-channel skew. Bonded transmitter datapath clocking provides low channel-to-channel skew when compared with non-bonded channel configurations.
  • Bonded channel configurations—the serial clock and parallel clock for all bonded channels are generated by the transmit PLL and central clock divider, resulting in lower channel-to-channel clock skew.

    The transmitter phase compensation FIFO in all bonded channels share common pointers and control logic generated in the central clock divider, resulting in equal latency in the transmitter phase compensation FIFO of all bonded channels. The lower transceiver clock skew and equal latency in the transmitter phase compensation FIFOs in all channels provide lower channel-to-channel skew in bonded channel configurations.

  • Non-bonded channel configurations—the parallel clock in each channel are generated independently by its local clock divider, resulting in higher channel-to-channel clock skew.

    The transmitter phase compensation FIFO in each non-bonded channel has its own pointers and control logic that can result in unequal latency in the transmitter phase compensation FIFO of each channel. The higher transceiver clock skew and unequal latency in the transmitter phase compensation FIFO in each channel can result in higher channel-to-channel skew.