Overview

Atria Logic Pvt. Ltd. provides the complete design services for PCI Express. (2.5GT/s, 5GT/s) Our expertise covers the breadth of PCI-SIG's 3.0 specification of PCIe. We have a highly skilled team of experts who can deliver the services on PCIe physical layer including

MAC

PCS

PIPE interface (8 bit, 16 bit and 32 bit interface)

Scrambler

The PHY layer is essentially the PIPE (Physical Interface for PCIe Express). The designed PIPE interface follows the INTEL's PIPE spec. This Intel's spec is being used by other vendors like Xilinx, Altera and PLDA with slight modifications in LTSSM and power management states. However the basic Interface mentioned in Intel's spec is maintained by all vendors and so our design.

Architecture

The main goal of Physical Layer is to establish the physical connection or channel for proper communication of transactions coming from above layer (Transaction Layer and Data Link Layer).

The main functions of Tx side of PHY layer are listed below

• Link training through ordered sets TS1 & TS2
• Insertion of SKP ordered sets every 1538 symbols for elastic buffer overflow/underflow management.
• Sending Logical Idles in particular state of LTSSM and whenever there is no data available to send.
• Sending ElOS (Electrical Idle) as dictated by ASPM and Software Power management.
• Sending FTS(Fast Training Sequence) ordered sets whiling coming back to active state from Low power state.
• Generation of PIPE signals which includes
• Tx_data[32 or 16 bit]
• D/K [4 or 2bit]
• Tx_Elec_Idle
• Tx_Compliance
• Rate[1:0]
• Width [1:0]
• Pwr_dwn[2:0]
• Reset_PhY
• TxdetectRx
• Insertion of STP, SDP, END kontrol characters (Implemented in DLL)

All the Data packets except Kontrol characters and ordered sets will pass through scrambler.

Block Diagram