One of the fundamental design facts of a pc is that its
microprocessor is always faster than the peripheral device to which it must
communicate. This fact has forced designed to develop interfaces that server as
buffers between the slower devices and the faster CPU to match up their speeds
and help with the timing of the operations. The very first PCs had an
individual chip to control each of the various operations.
It was common for an early PC to
have the following separate chips.
1. MATHS CO PROCESSOR
CHIP:-This chip helps in the flow of data between the processor and math
coprocessor.
3. BUS CONTROLLER
CHIP:-This chip controls the flow of data on the motherboard’s buses.
4. DMA CONTROLLER
CHIP:-This chip controls the process that allowed peripheral devices to
interconnect with memory without involving the processor.
5. PPI CHIP(Programmable Peripheral Interface):-This chip
supervises some of the simpler peripheral device.
7. CRT CONTROLLER
CHIP:-This chip facilities the PC’s display.
8. UART
(Universal Asynchronous Receiver Transmitter):-This chip used to send and receive
synchronous serial data.
CHIP-SET CHARACTERISTICS
The characteristics of a chip-set can be broken down into
six categories:
1) HOST:-This
category defines the host processor to which the chipset is matched along with
its bus voltage, usually GLT+ (Gunning Transceiver Logic Plus) or
AGTL+(Advanced Gunning Transceiver Logic Plus) and the number of processors
this chipset will be supported.
2) MEMORY:-This
category defines the characteristics of the DRAM support in the chipset,
including the DRAM refresh technique supported, the amount of memory supported
(in megabits usually) the type of memory supported and whether interleave, ECC (Error-Correcting
Code) or parity is supported.
3) INTERFACE:-This
category defines the type of PCI interface implemented and whether the chipset
is AGP-compliant, support integrated graphics, PIPE (Pipelining) or SBA (Side
Band Addressing).
4) ARBITRATION:-This
category defines the method used by the chipset to arbitrate between different
bus speeds and interfaces. The two most common arbitration methods are MTT
(Multi-Transition Timer) and DIA (Dynamic Intelligent Arbiter).
5) SOUTH BRIDGE
SUPPORT:-All Intel chipsets and most of the chipsets for all other manufactures
are two processor sets. In these sets, the north bridge is the main chip and
handles CPU and memory interfaces among other tasks, while the south bridge (or
the second chip) handles such things as the USB and IDE interfaces, the RTC
(Real Time Clock) and support for serial and parallel ports.
6) POWER
MANAGEMENT:-All Intel chipsets support both the SMM (System Management Mode)
and ACPI (Advanced Configuration and Power Interface) power management
standers
Chip-Set Built-in Controller
The controller and devices include in a chipset are
typically those that are common to virtually every PC of the type the chipset
is designed to support. The controller and devices usually include in a
chipset are as follow
1. MEMORY
CONTROLLER:-This is the logic circuit that controls the reading and writing of
data to and from system memory (RAM).Other device on the PC wishing to access
memory must interface with the memory controller. This feature also usually
includes error handling to provide for parity checking and ECC
(Error-Correcting Code) for every memory word.
2. EIDE
CONTROLLER:-Nearly all mid-to upper range motherboards now include at least one
EIDE connector for hard disk, floppy disks, CD-ROMs, DVDs or other types of
internal storage drives. The EIDE controller typically supports devices with
ISA, ATA and perhaps an ATA-33 or Ultra – DMA (UDMA) interface.
3. PCI BRIDGE:-Like
a network bridge that connects two dissimilar networks, this device logically
connects the PCI expansion bus on the motherboard to the processor and other
non-PCI device.
4. RTC (REAL TIME
CLOCK):-This clock holds the date and time on your pc; this is the date and
time is displayed to you on the monitor and is used to date-stamp file
activities. This should not be confused with system clock that provides the
timing signal for the processor and other devices.
5. DMA CONTROLLERS
(DIRECT MEMORY ACCESS):- The DMA controller manages the seven DMA channel
available for use by ISA/ATA devices on most PCs. DMA channel are used by
certain devices, such as floppy disk
drives, such as floppy disk drive , sound card , SCSI adapters and some network
adapters, to move data into memory without the assistance of the CPU.
6. IRDA CONROLLER
(Infrared Data Association):-It is the international organization that has
created the standards for short- range line of sight, point to point infrared
device, such as a keyboard, mouse and network adapters.
7. KEYBOARD CONTROLLER:-A chipset may include the
keyboard controller and many of the newer once do. The keyboard controller is
the interface between the keyboard and the processor.
8. PS/2 MOUSE
CONTROLLER:-When IBM introduced the ps/2 system, the controller for the mouse
was included in the keyboard controller. This design has persisted and usually
whenever the keyboard controller is, so is the ps/2 mouse controller. This
device provides the interface between the ps/2 mouse and the processor.
9. SECONDARY CACHE
CONTROLLER (L2):-It is located on the motherboard, a daughter board or as on
the Pentium pro, in the processor package and caches the primary memory (RAM)
the hard disk and the CD-ROM drive. The secondary cache controller controls the
movement of data to and from the L2 cache and the processor.
10. CMOS SRAM:-The
PC’s configuration settings are stored in what is called the CMOS memory. The
chipset contains the controller used to access and modify this special SRAM
area.
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