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