SOC Design Lecture 4

Bus and AMBA Introduction

YOUPYO HONG, DGU

Road without Traffic Lights

2

YOUPYO HONG, DGU

Communication between Multiples

3

YOUPYO HONG, DGU

Bus

4

bus

YOUPYO HONG, DGU

Two Types of Connections

RegisterRegister Register

RegisterRegister

RegisterRegister Register

RegisterRegister

Point-to-Point Connection Common Bus-based Connection

5

YOUPYO HONG, DGU

Bus

A subsystem that transfers data or signals between digital components .

Unlike a point-to-point connection, a bus can connect multiple components over the same set of wires.

Each bus defines its set of signals to physically connect components together.

The definition of the signals implicitly include the protocols on how to use the signals.

6

YOUPYO HONG, DGU

First Generation Bus

A bundles of wires connected to CPU pins directly.

Memory and other devices are added to the bus using the same address and data pins as the CPU itself in parallel.

Drawbacks All component must have same clock -> limited clock

frequency CPU is busy due to heavy bus transactions. -> low

throughput. Examples : Early IBM PCs in 1980s.

7

YOUPYO HONG, DGU

Second Generation Bus

Separated the system into two "worlds", the CPU and memory on one side, and the various devices on the other, with a bus controller in between.

CPU can now be free from slow peripheral bottleneck.

Shortcomings A lot of bus controllers (for each slot in a computer.)

Examples : SCSI, IDE

8

YOUPYO HONG, DGU

Widely Known Buses

Parallel Industry Standard Architecture or ISA Advanced Technology Attachment or ATA (aka PATA, IDE, EIDE,

ATAPI, etc.) disk peripheral attachment bus Peripheral Component Interconnect or PCI PC card, previously known as PCMCIA, SCSI Small Computer System Interface (disk peripheral attachment)

Serial 1-Wire HyperTransport I²C PCI Express or PCIe Serial Peripheral Interface Bus or SPI bus USB Universal Serial Bus

9

YOUPYO HONG, DGU

Bus for SOC

SOC needs a bus, of course. SOC bus should support

Modular system designTechnology-independence Easy to useLight in size and complexity

10

YOUPYO HONG, DGU

AMBA

Stands for Advanced Microcontroller Bus Architecture

Developed by ARM in 1990s (England) ARM also developed ARM RISC series for

SOC applications. ARM is now the mostly widely used RISC

core and that makes AMBA most popular BUS in SOC world.

11

YOUPYO HONG, DGU

Typical AMBA System

ASB is not used these days.

12

YOUPYO HONG, DGU

Key AMBA Version

AMBA 2.0 : AHB, APB, ASB

AMBA 3.0 : AXI

13

YOUPYO HONG, DGU

HW #1 (Due in next class)

Visit ww.arm.com and search AMBA specifications.

For AHB and AXI respectively, find out the followings and submit them in a report.Years they are made.The number of signals.