(Industry Standard Architecture)

TIPE-TIPE BUS
 BUS ISA
Bus ISA (Industry Standard Architecture) adalah sebuah bus PC/AT (16 bit) yang beroperasi pada
8,33 MHz

BUS PCI
Bus PCI (Peripheral Component Interconnect bus)
Bus yang beroperasi pada kecepatan 33 MHz


BUS Seri Universal
Sebuah bus standart yang disepakati bersama oleh tujuh perusahaan untuk digunakan pada peralatan berkecepatan rendah

 A bus connects all the internal computer components to the CPU and Main memory.
 Every bus has a clock speed measured in
MHz. A fast bus allows data to be transferred faster, which makes applications run faster.
On PCs, the old ISA bus is being replaced by faster buses such as PCI.

 System Bus: Connecting to CPU, memory and Cache.



Address Bus
Data Bus
Control Bus
 I/O Bus: Connecting to the above three buses is the "good old" standard I/O bus, used for slower peripherals (mice, modems, regular sound cards, low-speed networking) and also for compatibility with older devices. On almost all modern PCs this is the Industry Standard Architecture (ISA) bus.

Saluran data memberikan lintasan bagi perpindahan data antara dua modul sistem .
- Besar jalur bus data mempengaruhi kinerjanya, contoh : 8, 16, 32 dan 64 bit

- Identifikasi sumber atau tujuan data pada bus data
- Mengalamati port-port I/O
- Contoh : jika CPU akan membaca word ( 8, 16 atau 32 bit) data dari memori maka CPU akan menaruh alamat word yang dimaksud pada saluran alamat

- Mengontrol akses ke saluran alamat dan penggunaan data dan saluran alamat.
- Mengendalikan dan mengatur timing informasi : a. Sinyal read /write b. Interrupt request c. Sinyal clock

Memory
CPU
I/O module
“CPU bus” or
“System bus”
“Bus interface” “I/O bus”
I/O device

 PCI Local bus
 ISA
 AGP
 Micro Channel (MCA)
 PC-Card (PCMCIA)
 EISA
 VESA Local bus (VL-bus)
 USB
 Fire Wire (IEEE-1394)

Bus ISA ( Industry Standard Architecture ) adalah sebuah arsitektur bus dengan bus data selebar 8-bit yang diperkenalkan dalam IBM PC 5150 pada tanggal
12 Agustus 1981 .
Bus ISA diperbarui dengan menambahkan bus data selebar menjadi 16-bit pada
IBM PC/AT pada tahun 1984 , sehingga jenis bus ISA yang beredar pun terbagi menjadi dua bagian, yakni ISA
16-bit dan ISA 8-bit. ISA merupakan bus dasar dan paling umum digunakan dalam komputer IBM PC hingga tahun 1995 , sebelum akhirnya digantikan oleh bus PCI yang diluncurkan pada tahun 1992 .

 ISA BUS (8-16-bit)
 EISA (Extended Industry Standard
Architecture) BUS (32-bit)
 PCI (Peripheral Component Interconnect)
BUS (32 or 64-bit)
 AGP (Accelerated Graphic Port)
(32-bit)

ISA BUS
8-bit
16-bit

ISA BUS
8-bit ISA BUS 16-bit ISA BUS
Bus width 8 - bit
Compatible with 8 bit ISA
Pins
Power
Clock
62
+5 V, -5 V, +12 V, -12 V
4.7727266 MHz
Bus width 16 - bit
Compatible with 16 bit ISA
Pins
Power
Clock
98
+5 V, -5 V, +12 V, -12 V
8.333333 MHz

ISA BUS
 is used with sound cards, disk drives or most network and video cards.
8-bit ISA(XT) CARD 16-bit ISA CARD

ISA BUS
ISA Card

ISA BUS
VESA connectors
Additional connections converts to 16 bit
ISA
Original 8 bit ISA connectors

3 ISA slots
5 PCI slots
Pentium
CPU
6 SIMM slots
2 DIMM slots

ISA BUS
In the figure you can see the pinouts of the ISA BUS. The BUS is divided into two sides. The first side pins are named
A1 to A31 and it is the components side.
It consists of the address and data buses.
The second side pins are named
B1 to B31 and it is the solder side. This side contents the power pins and the signals related to interrupts and DMA transfers.

ISA BUS
More
DMA lines
IRQ lines
8 - 15
IRQ lines
2-7 clock
More
DMA lines
± 5, ±12V
Power & G
Extra 8 bits of
I/O bus
Extra 4 bits of
Address bus
20 bits of Address bus
16 bit
8 bits of I/O bus
Original 8 bit ISA














ISA BUS
A0-A19 (pins A31 to A12): This twenty lines are the address BUS.
They can address 1MB (2^20 bytes).
D0-D7 (pins A9 to A2): The data BUS consist of this eight data lines.
AEN (pin B11): It is used for the DMA controller to take over the data and address buses in a DMA transfer.
GND (pins B1, B10, B31): Connected to the ground of the computer.
+5V (pins B3, B29): 5V DC output of the power source.
-5V (pin B5): -5V DC output.
-12V (pin B7): -12V DC output.
+12V (pin B9): +12V DC output.
MEMW (pin B11): The µP asserts this signal when doing a write to the memory .
MEMR (pin B12): The µP asserts this signal when doing a read from the memory .
IOW (pin B13): The µP asserts this signal when doing a write to a port .
IOR (pin B14): The µP asserts this signal when doing a read from a port .
DACK0-DACK3 (pins B15, B17, B19 and B26): The DMA controller sets this signals to let a device know that the DMA has the control of the buses.
DRQ1-DRQ3 (pins B6, B16 and B18): Allow the peripheral boards to request the use of the buses.
+T/C (pin B27): The DMA controller sets this signal to let the peripheral know that the programmed number of bytes has been sent.
IRQ2-IRQ7 (pins B4, B21, B22, B23, B24 and B25): Interrupt signals. The peripheral devices sets this signals to request for the attention of the µP.
ALE (pin 28): This signal is used for the µP to lock the 16 lower address BUS in a latch during a memory
(or port) input/output operation.
CLOCK (pin 20): Is the system clock.
OSC (pin 30): Is a high frequency clock which can be used for the I/O boards.

Describing the Read operation of the ISA
 CPU sends out a high on the
ALE signal, then sends out the A0-A19 lines. On the address of the target port to be read will be latched. Then the BUS takes the -IOR signal to a low level. So that the addressed device will take a data byte to the D0-
D7 data bus. The microprocessor will read then the data bus and take the -
IOR signal to a high again.

Describing the Read/Write operation of the ISA
 The only difference between a memory read/write cycle and a port read/write cycle is that in a memory cycle the -MEMR and -MEMW signals will be asserted, working the same way as -IOR and -IOW do.

ISA BUS
 Int e l
 80386DX
 CPU
A
0 to A
31
Address bus(32 bit)
D
0 to D
31
Data bus (32 bit)
RD WR IO/M
Control bus
I/O bus
(16 bit data)
Memory
Keyboard
Storage
Printer
Video
Modem

CPU
Memory
Local bus or CPU bus: fast (33 MHz, 32 bits) [30 nsec./cycle]
Cache
Video
Adapter
Disk
“ISA BRIDGE”
Expansion
Bus
Controller
System
ROM
ISA bus: slow (8 MHz, 8/16 bits) [125 nsec./cycle]
RTC Keyboard
Serial
Port
Parallel
Port
Floppy
Disk

Pentium
CPU
CPU bus: fast (100 MHz, 64 bits) [10 nsec./cycle]
“North Bridge”
Cache
PCI
Controller
PCI bus: fast (33 MHz, 32/64 bits) [30 nsec./cycle]
Memory
Video
Adapter
Disk
System
ROM
“South Bridge”
Expansion
Bus
Controller
ISA bus: slow (8 MHz, 8/16 bits) [125 nsec./cycle]
RTC Keyboard
Serial
Port
Parallel
Port
Floppy
Disk

NORTH BRIDGE
CPU Bus
M/IO #(memory or i/o address)
D/C# (Data or code)
W/R# (Write or Read)
AEN#
BRDY# (Burst Ready)
A31-A3 (Address Lines)
BE7# - BE0# (Byte Enable
Lines)
D31-D0
Expansion
Bus
Controller
PCI Bus
FRAME#
TRDY#
IRDY#
STOP#
REQ#
GNT#
AD[31:0]
C/BE#[3:0]
CLK

PCI Bus
FRAME#
TRDY#
IRDY#
STOP#
REQ#
GNT#
AD[31:0]
C/BE#[3:0]
SOUTH BRIDGE
Expansion
Bus
Controller
ISA Bus
MEMR#
MEMW#
ALE
IOR#
IOW#
INTA#
A23-A0
D23-D0
CLK

ISA BUS INTERRUPT SYSTEM
 16-bit ISA bus chains two 8259As together.
 IRQ 9 is used to re-route anything trying to use IRQ 2.
 Incorporated in chip set.

INTERRUPT CONTROLLER
(IRQ 2)
8259A
IRQ0 (8)
IRQ1 (9)
IRQ2 (10)
IRQ3 (11)
IRQ4 (12)
IRQ5 (13)
IRQ6 (14)
IRQ7 (15)
8259A
IRQ0
IRQ1
IRQ2
IRQ3
IRQ4
IRQ5
IRQ6
IRQ7
80x86
INTR

Elimination of ISA Bus
 ISA Bus is slow, hard to use and bulky.
 ISA plug in cards to be replaced by either PCI plug-in cards or USB add-on peripherals
 Limited number of interrupts.
 No central registry.

Elimination of ISA Bus
 The ISA bus is limited to 24 bits of address. 2^24 = 16 MBytes . It means that an ISA card that uses DMA cannot physically access memory beyond 16
MBytes of RAM. This is a limitation of the
ISA bus.

Elimination of ISA Bus
 Motherboard gets 32-bit data from ISA BUS at two times. Meanwhile at this time ISA BUS declares “wait state” to the motherboard.
Therefore ISA BUS may reduce System
Performance.

Elimination of ISA Bus
 If you use a ISA based controller card such as Ultra SCSI - 40Mb / sec or
SCSI-2 Fast - 10 Mb / sec , you can expect no more than an 8Mb per second transfer rate from your controller card.

Elimination of ISA Bus

PCI cards have “Plug and Play” technology and can configure themselves, so Operating
Systems distinguish them.
 ISA cards are more cumbersome to install than other cards because I/O addresses, interrupts and clock speed must be set using jumpers and switches on the card itself.

Elimination of ISA Bus
Bus Type
VL-bus
VL-bus
32-Bit PCI
PCI-X 66
PCI-X 133
AGP x1
AGP x2
AGP x4
AGP x8
PCI Express x1
PCI Express x2
PCI Express x4
PCI Express x8
PCI Express x12
PCI Express x16
MB/sec
100 MBps
132 MBps
132 MBps
512 MBps
1 GBps
264 MB/s
528 MB/s
1056 MB/s
2112 MB/s
500 MB/s
1000 MB/s
2000 MB/s
4000 MB/s
6000 MB/s
8000 MB/s