Stratix V Device Handbook: Volume 2: Transceivers

ID 683779
Date 11/23/2021
Document Table of Contents

1.2.3. Receiver Deserializer

The deserializer block clocks in serial input data from the receiver buffer using the high-speed serial recovered clock and deserializes the data using the low-speed parallel recovered clock. The deserializer forwards the deserialized data to the receiver PCS or FPGA core.

The deserializer in the RX PMA also provides a clock slip feature. The word aligner block in the PCS can contribute up to one parallel clock cycle of latency uncertainty. You can use the clock slip/bit slip feature to control the word alignment instead, so that you can reduce the latency uncertainty, ensuring deterministic latency. The deterministic latency state machine in the word aligner (within the PCS) automatically controls the clock slip/bit slip operation. The de-serializer first performs clock slip/bit slip, after which the parallel data is word-aligned in the RX PCS. These features are for protocols like CPRI that require deterministic latency through the PHY layer.

The GX channel deserializer supports 8- and 10-bit, 16- and 20-bit, 32- and 40-bit factors. 64-bit factors are also supported depending on the transceiver configuration. Unlike the GX channel deserializer, the GT channel deserializer does not support programmable data widths and is fixed at 128 bits.