CHIPSET

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.

 2. CLOCK GENERATOR CHIP:-T his chip controls the flow of the PC’s operations.

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.

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6. FDC CHIP (FLOPPY DISK CHIP):-This chip controls the PC’s diskette and tape derives.

 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.