http://en.wikipedia.org/wiki/Advanced_Microcontroller_Bus_Architecture
The Advanced Microcontroller Bus Architecture (AMBA) is used as the on-chip bus in system-on-a-chip (SoC) designs. Since its inception, the scope of AMBA has gone far beyond microcontroller devices, and is now widely used on a range of ASIC and SoC parts including applications processors used in modern portable mobile devices like smartphones.
AMBA is a registered trademark of ARM Limited,[1] and is an open standard, on-chip interconnect specification for the connection and management of functional blocks in a System-on-Chip (SoC). It facilitates right-first-time development of multi-processor designs with large numbers of controllers and peripherals.
AMBA was introduced by ARM Ltd in 1996. The first AMBA buses were Advanced System Bus (ASB) and Advanced Peripheral Bus
(APB). In its 2nd version, AMBA 2, ARM added AMBA High-performance Bus (AHB) that is a single clock-edge protocol. In 2003, ARM introduced the 3rd generation, AMBA 3, including AXI to reach even higher performance interconnect and the Advanced Trace Bus (ATB) as part of the CoreSight on-chip debug and trace solution. In 2010 the AMBA 4 specifications were introduced starting with AMBA 4 AXI4, then in 2011[2] extending system wide coherency with AMBA 4 ACE. In 2013[3] the AMBA
5 CHI (Coherent Hub Interface) specification was introduced, with a re-designed high-speed transport layer and features designed to reduce congestion.
These protocols are today the de facto standard for 32-bit embedded processors because they are well documented and can be used without royalties.
Conventional PCI - Wikipedia
PCI Local Bus
Three 5-volt 32-bit PCI expansion slots on a motherboard (PC bracket on left side)
Year created July 1993
Created by Intel
Supersedes ISA, EISA, MCA, VLB
Superseded by PCI Express (2004)
Width in bits 32 or 64
Capacity 133 MB/s (32-bit at 33 MHz--the standard configuration)
266 MB/s (32-bit at 66 MHz or 64-bit at 33 MHz)
533 MB/s (64-bit at 66 MHz)
Style Parallel
Hotplugging interface Optional
Conventional PCI (PCI is an initialism formed from Peripheral Component Interconnect,[1] part of the PCI Local Bus standard), often shortened to just PCI, is a local computer bus for attaching hardware devices in a computer. The PCI bus supports the functions found on a processor bus, but in a standardized format that is independent of any particular processor. Devices connected to the bus appear to the processor to be connected directly to the processor bus, and are assigned addresses in the processor's address space.[2]
Attached devices can take either the form of an integrated circuit fitted onto the motherboard itself, called a planar device in the PCI specification, or an expansion card that fits into a slot. The PCI Local Bus was first implemented in IBM PC compatibles, where it displaced the combination of ISA plus one VESA Local Bus as the bus configuration. It has subsequently been adopted for other computer types.
The PCI specification covers the physical size of the bus (including the size and spacing of the circuit board edge electrical contacts), electrical characteristics, bus timing, and protocols. The specification can be purchased from the
PCI Special Interest Group (PCI-SIG).
Typical PCI cards used in PCs include: network cards, sound cards, modems, extra ports such as USB or serial, TV tuner cards and disk controllers. PCI video cards replaced ISA and VESA cards, until growing bandwidth requirements outgrew the capabilities of PCI; the preferred interface for video cards became AGP, and then PCI Express. PCI video cards remain available for use with old PCs without AGP or PCI Express slots.[3]
PCI and PCI-X have become obsolete for most purposes, however, they are still common on modern desktops for the purposes of backwards compatibility and the low relative cost to produce. Many kinds of devices previously available on PCI expansion cards are now commonly integrated onto motherboards or available in universal serial bus and PCI Express versions.
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