SerDes (Serialization/DeSerialization)

The simple goal of the SerDes peripheral is twofold convert SOC parallel data into serialized data that can be output over a high-speed electrical interface, and convert high-speed serial input data into parallel data that the SOC can process.

At its most basic, the SerDes is comprised of:

1. Clock Multiplier Unit (CMU): The CMU handles peripheral and TX clocking of the SerDes. It consists of an internal PLL and the reference clock input buffers.
2. Lanes: The lanes handle all inputs and outputs from the serial interface, and contain the TX/RX I/Os, serializers/deserializers, and CDR. A SerDes peripheral can have either two or four lanes.
3. Physical Coding Sub-block (PCS): The PCS is responsible for translating data from/to the parallel interface, encoding/decoding, and symbol alignment.
4. WIZ: The WIZ acts as a wrapper for the SerDes peripheral, and can both send control signals to and report status signals from the SerDes.

Transmission (Serializer)

•Parallel-to-Serial Conversion: The SerDes device receives parallel data, typically in the form of bytes or words from the data source.

•Data Serialization: The SerDes converts the parallel data into a serial bit stream. This involves arranging the bits from the multiple data lines into a single serial data stream.

•Clock Generation: A clock signal is generated to ensure synchronized transmission. This clock is typically embedded in the serial data stream or transmitted separately.

•Encoding and Modulation: Depending on the communication standard and channel characteristics, modulation techniques may be applied to the serial data stream to improve signal integrity and error tolerance.

•Pre-emphasis/Equalization: To compensate for the signal attenuation and distortion over the communication channel pre-emphasis and equalization techniques may be employed.

Reception (Deserializer)

•Serial-to-Parallel Conversion: The SerDes device receives the serialized data stream along with the clock signal.

•Clock Recovery: The receiver recovers the clock signal from received data to correctly sample the incoming bits.

•Decoding and Demodulation: If encoding and modulation were applied during transmission and demodulation is performed to extract the original data.

•Parallel Data Reconstruction: The serialized data is converted back into parallel data which can be further processed or sent to the destination.

•Error Detection and Correction: Error detection and correction techniques are applied to ensure data integrity, especially in noisy or high-speed channels.

•Post-equalization: The Post-equalization techniques may be used to further compensate for the signal distortion before delivering the data to the receiver.

The evolution of high-speed SerDes interfaces was driven by demand for the increased data rates, reduced signal skew, and minimized noise interference in the high-speed communication links. As technology advanced, need for the higher bandwidth and improved signal integrity in data communication led to the development of the SerDes interfaces capable of operating at gigabit-per-second and even terabit-per-second data rates.

The evolution of high-speed SerDes interfaces has revolutionized various industries enabling the rapid growth of high-speed data communication, data centers, telecommunications, and high-performance computing.

There are several types of SerDes interfaces which include:

1. Single-Channel SerDes
2. Multi-Channel SerDes
3. PAM4 SerDes
4. LVDS SerDes
5. PCIe SerDes
6. RF SerDes