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PCIe - TLP Header, Packet Formats, Address Translation, Config Space, Command Register, Configuration types

TLP Packet Format: FIG: TLP Packet Format. The Transaction Layer Packet Format is defined as: Starts with a Prefix, which is an optional one and, TLP Header and then, With/Without Data Payload, At the end of TLP Packet a TLP Digest, The information in TLP Packet Format is distributed as: TLP Prefixes. Header (mandatory). Data (included when applicable): depends on the transaction type. TLP Digest (optional). FIG: TLP Byte Information TLP Header: Provides Format of the packet. Type of the packet. Length of associated data, if available. Transaction Descriptor. Address/Routing information Byte enables Message encoding Completion Status FIG: Common TLP Header. 32-bit if information. Provides: Format, TLP Packet Type, Traffic Class info, Attributes, T Heads (Presence of TLP Prefix, if present), TLP Digest, End Point (TLP is Normal or Poisoned), Address Translation (When memory is available). Length (Data Length notation denoted in 32bit words) F...

PCI Configuration Space Registers (Type 0 / Type 1)

PCI Configuration Space Type 0 is for PCI devices and, for Endpoints in case of PCIe. Type 1 Config Space is for PCI host controller and, for PCI Root Complex in case of PCIe. Type 0/1 Configuration Space: FIG: Config Space. The Config Space registers are common for both type 0/1. Device ID and Vendor ID: Identify the particular device. Status register: Provides error information, updated information, etc. Command register: Controls Bus Master and different utilities. Class code: Provides category of the device (Host Controller, IDE Bridge, SATA Controller, Ethernet Controller, etc). Revision ID of PCI. BIST - Built-In Self Test. Header Type Specific area is defined by Header type (0 or 1). Cache Line Size. Table: Configuration Space Registers. Table: Command Register Table: Status Register FIG: Type 0 Configuration Space Table: TYPE 0 Registers FIG: PCIe TYPE 1 Configuration Space Table: TYPE 1 Configuration Space Registers

PCIe - Terminology, Throughput, Root Complex, End Point and, Switch

In my previous post, I introduced the topology and architecture of PCIe. After a careful study, I have gathered a detailed understanding of its terminology and working. Let's have a look! FIG: Various PCIe slots on a motherboard- PCIe x 4; 16; 1; 16; Conventional 5V 32Bit PCI, respectively. Source: Wikipedia Terminology: FIG: PCIe link between two devices consisting of one or more lane. Source: Wikipedia Switch, n-point, root complex can be directly connected with the PCIe Link. Link contains high-speed serial standard bus, which has a differential signaling. Diffrential signaling are software interrupts sent to a program to indicate an important event like user requests or illegal memory access errors (One transmit pin having two pairs of wires: Transmit +ve and -ve which increases noise immunity). *You can use kill -l on your linux/unix system to view the supported signals. For example: If +ve is affected with noise, and in a similar manner if -ve also gets ...

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Electrical Engineering

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