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SIM: is Set Interrupt MASK. USED to mask the hardware interrupts.

RIM: is Read Interrupt Mask. Used to CHECK whether the interrupt is Masked or not.

SIM: is Set Interrupt Mask. Used to mask the hardware interrupts.

RIM: is Read Interrupt Mask. Used to check whether the interrupt is Masked or not.

3 MHz is the MAXIMUM CLOCK FREQUENCY for 8085.

3 MHz is the maximum clock frequency for 8085.

In primary STORAGE device the storage capacity is limited. It has a VOLATILE memory. In SECONDARY storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM. Secondary devices are: FLOPPY disc / Hard disk.

In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM. Secondary devices are: Floppy disc / Hard disk.

The 128 BYTES of on-chip additional RAM locations from 80H to 0FFH are reserved for the special functions and therefore these are called as special FUNCTION REGISTER.

The 128 bytes of on-chip additional RAM locations from 80H to 0FFH are reserved for the special functions and therefore these are called as special function register.

ACCUMULATOR, B-register, R0- R7

Accumulator, B-register, R0- R7

1. PROGRAM COUNTER
2. DATA POINTER

Harvard architecture uses separate memories for program and data MEMORY WHEREAS VON Neuman uses same program and data memory.Therefore Harvard is faster compared to other ONE.

Harvard architecture uses separate memories for program and data memory whereas Von Neuman uses same program and data memory.Therefore Harvard is faster compared to other one.

It must have RAM and rom to SUPPORT its inbuilt functions. It must have +5V SUPPLY, must be FAST and should have programmable and data memory.

It must have ram and rom to support its inbuilt functions. It must have +5v supply, must be fast and should have programmable and data memory.

RISC CHIPS requires LESSER hardware IMPLEMENTATIONS, which makes them simpler to design and hence lesser costs of PRODUCTION.

RISC chips requires lesser hardware implementations, which makes them simpler to design and hence lesser costs of production.

The first main advantage is that the ALUS can be assembled together horizontally to form computers that can handle very large DATA at a TIME. Another advantage is BIT slice design that makes use of possible bipolar CHIP technology that is very fast.

The first main advantage is that the ALUs can be assembled together horizontally to form computers that can handle very large data at a time. Another advantage is bit slice design that makes use of possible bipolar chip technology that is very fast.

The devices that has all the FUNCTIONAL BLOCKS on chip, INCLUDING the program and data MEMORY and there is no external data/address bus provided. For example, ATMEL89C2051.

The devices that has all the functional blocks on chip, including the program and data memory and there is no external data/address bus provided. For example, ATMEL89C2051.

An INTERRUPT that can be TURNED off by the PROGRAMMER is KNOWN as Maskable interrupt.

An interrupt that can be turned off by the programmer is known as Maskable interrupt.

5 Mhz is the MAXIMUM clock FREQUENCY in 8086.

5 Mhz is the Maximum clock frequency in 8086.

There are three types of buses.

• Address bus: This is used to carry the Address to the memory to fetch EITHER Instruction or Data.
• Data bus : This is used to carry the Data from the memory.
• Control bus : This is used to carry the Control signals like RD/WR, Select ETC.

There are three types of buses.

BYTE CONTAINS 8 COMBINATIONS of BITS.

Byte contains 8 combinations of bits.

Intel’s 80386 was the first 32-bit processor, and since the company had to backward-support the 8086. All the modern Intel-based processors run in the ENHANCED MODE, CAPABLE of switching between Real mode (just like the real 8086) and Protected mode, which is the current mode of operation.

Intel’s 80386 was the first 32-bit processor, and since the company had to backward-support the 8086. All the modern Intel-based processors run in the Enhanced mode, capable of switching between Real mode (just like the real 8086) and Protected mode, which is the current mode of operation.

IEEE 1394 (Firewire) supports the maximum of 63 connected DEVICES with SPEEDS up to 400 Mbps. Where’s MBR located on the disk? Main BOOT Record is located in sector 0, track 0, head 0, cylinder 0 of the primary active partition.

IEEE 1394 (Firewire) supports the maximum of 63 connected devices with speeds up to 400 Mbps. Where’s MBR located on the disk? Main Boot Record is located in sector 0, track 0, head 0, cylinder 0 of the primary active partition.

High-end: Intel – Pentium (II, III, 4), AMD – Athlon. Low-end: Intel – Celeron, AMD – Duron. 64-bit: Intel – Itanium 2, AMD – OPTERON.

High-end: Intel – Pentium (II, III, 4), AMD – Athlon. Low-end: Intel – Celeron, AMD – Duron. 64-bit: Intel – Itanium 2, AMD – Opteron.

The processor made of PMOS / NMOS / HMOS / HCMOS technology is CALLED 1st / 2nd / 3rd / 4th generation processor, and it is made up of 4 / 8 / 16 / 32 bits.

The processor made of PMOS / NMOS / HMOS / HCMOS technology is called 1st / 2nd / 3rd / 4th generation processor, and it is made up of 4 / 8 / 16 / 32 bits.

In 8086 Carry FLAG, Parity flag, Auxiliary carry flag, ZERO flag, Overflow flag, TRACE flag, INTERRUPT flag, Direction flag, and SIGN flag.

In 8086 Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.

Address Bus:Group of lines USED by the microprocessor to SEND the address of the device or the memory LOCATION which the microprocessor needs to access.The address BITS flow in one direction, ie, from the microprocessor to the peripheral devices.Hence the address bus is unidirectional.The width of the address bus determines the maximum NUMBER of memory locations that the microprocessor can access.

Address Bus:Group of lines used by the microprocessor to send the address of the device or the memory location which the microprocessor needs to access.The address bits flow in one direction, ie, from the microprocessor to the peripheral devices.Hence the address bus is unidirectional.The width of the address bus determines the maximum number of memory locations that the microprocessor can access.

Data Bus: Group of lines that transmit data in and out of the MICROPROCESSOR is called the data bus. Here the data can FLOW in both DIRECTIONS between the microprocessor and the peripheral devices. Hence the data bus is bidirectional. The width of the data bus depends on the architecture of the microprocessor. For an EXAMPLE, an 8 bit processor can operate on 8 BITS of data at a time and has a 8 bit wide data bus.

Data Bus: Group of lines that transmit data in and out of the microprocessor is called the data bus. Here the data can flow in both directions between the microprocessor and the peripheral devices. Hence the data bus is bidirectional. The width of the data bus depends on the architecture of the microprocessor. For an example, an 8 bit processor can operate on 8 bits of data at a time and has a 8 bit wide data bus.

Group of lines connecting the microprocessor with other components of a COMPUTER system is called a bus. It is a communication path over which electrical signals representing BINARY DIGITS ( 0, 1) are TRANSMITTED. For a single bit to transmit, one line is used. The WIDTH of the bus is number of lines that are used to constitute that bus.

Group of lines connecting the microprocessor with other components of a computer system is called a bus. It is a communication path over which electrical signals representing binary digits ( 0, 1) are transmitted. For a single bit to transmit, one line is used. The width of the bus is number of lines that are used to constitute that bus.

• A Flip-flop is a basic electronic CIRCUIT used for storing information in a DIGITAL MACHINE.
• It is a BISTABLE device. It means it has two stable states.
• It has ONE or more inputs and two complement outputs.

ROM - Read Only Memory
RAM - RANDOM ACCESS Memory
PROM - PROGRAMMABLE Read Only Memory
EPROM - Erasable Programmable Read Only Memory
EEROM - ELECTRICALLY Erasable Programmable Read Only Memory

ROM - Read Only Memory
RAM - Random Access Memory
PROM - Programmable Read Only Memory
EPROM - Erasable Programmable Read Only Memory
EEROM - Electrically Erasable Programmable Read Only Memory

• ROM - 4K BYTES
• RAM - 128 bytes
• Timer - 2 no
• I/O Pins - 32
• Serial PORT - 1
• Interrupt sources - 6

The microprocessor has no ROM, RAM and no I/O ports on the chip itself.Whereas the MICROCONTROLLER has a CPU in ADDITION to a FIXED amount of RAM,ROM, I/O ports and a timer all on a single chip.

The microprocessor has no ROM, RAM and no I/O ports on the chip itself.Whereas the microcontroller has a CPU in addition to a fixed amount of RAM,ROM, I/O ports and a timer all on a single chip.

• INTEL
• PHILIPS
• Infineon
• Maxim/Dellas SEMICONDUCTOR
• ATMEL

The important CRITERIA to be considered in choosing micro CONTROLLERS are:

• AVAILABILITY of software development tools like compilers, debuggers, assemblers
• Meeting the computing needs of the task at hand efficiently at low-cost.
• Wide availability
• Reliable sources/manufacturers
• The amount of RAM and ROM on chip
• The number of I/O pins and the timer on the chip
• Power consumption
• Speed of the DEVICE
• Packaging
• Cost per UNIT.

The important criteria to be considered in choosing micro controllers are:

Higher Reliability: Once the program written and tested it can be easily downloaded into other PLC's memory. It requires lesser and simpler wiring compared to conventional hard wired circuits EMPLOYED. Hence reliability of the system increases significantly with PLCs.
More Flexibility: It is easier to create a new program module or change an existing program in PLC compared to hard wired circuitry system. These software program modules can be changed whenever required. USE can modify the programs in the field and if required, security can be enhanced by hardware interlocks such as key locks and software features such as passwords.
Lower Cost: PLCs were originally designed to replace relay control logic which is not economical and complex especially for large control circuits. With PLCs the cost savings have been so significant that the relay control becomes uneconomical except for some power applications. Generally if the application consists of more than half a dozen control RELAYS, PLCs are least expensive to install.
Communication Capability: Communication capability of PLC with the other controllers and computers in the system is one of the main advantages compared to relay control circuit. Functions such as Supervisory control, data acquisition from the field, monitoring devices and process parameters associated with the field and downloading and uploading of programs can be easily POSSIBLE with the PLC compared to hardwired circuits.
Faster Response: PLCs are designed for high speed and for the real time applications.Response time for PLCs are much smaller compared to relay logic circuits. The programmable controllers operates in real time i.e, an event taking carrying out at field will result in execution of OPERATION of output.
Easy to Troubleshoot: PLCs have inbuilt diagnostics and override functions that helps the user to easily trance the software and hardware errors.

Higher Reliability: Once the program written and tested it can be easily downloaded into other PLC's memory. It requires lesser and simpler wiring compared to conventional hard wired circuits employed. Hence reliability of the system increases significantly with PLCs.
More Flexibility: It is easier to create a new program module or change an existing program in PLC compared to hard wired circuitry system. These software program modules can be changed whenever required. Use can modify the programs in the field and if required, security can be enhanced by hardware interlocks such as key locks and software features such as passwords.
Lower Cost: PLCs were originally designed to replace relay control logic which is not economical and complex especially for large control circuits. With PLCs the cost savings have been so significant that the relay control becomes uneconomical except for some power applications. Generally if the application consists of more than half a dozen control relays, PLCs are least expensive to install.
Communication Capability: Communication capability of PLC with the other controllers and computers in the system is one of the main advantages compared to relay control circuit. Functions such as Supervisory control, data acquisition from the field, monitoring devices and process parameters associated with the field and downloading and uploading of programs can be easily possible with the PLC compared to hardwired circuits.
Faster Response: PLCs are designed for high speed and for the real time applications.Response time for PLCs are much smaller compared to relay logic circuits. The programmable controllers operates in real time i.e, an event taking carrying out at field will result in execution of operation of output.
Easy to Troubleshoot: PLCs have inbuilt diagnostics and override functions that helps the user to easily trance the software and hardware errors.

Programmable Logic Controllers (PLCS) have basic architecture COMPARED to normal general purpose computers. A normal computer can be converted to PLCs by providing a way that the computer can able to receive information or signal from the field devices such as push buttons, switches and valve positions. Computer requires a some software to process the information OBTAINED from the input to generate an output which decide whether to close or open the valve position in the process side.

Some of the important features and characteristics that distinguish between the general purpose computers and Programmable Logic Controllers(PLCs) are given below:

• PLCs are designed to operate under industrial environments (PLCs have to operate under wide range of temperature conditions, humidity and other environmental conditions). They are least affected by the electrical noise and are inherent to electrical noise Programming in PLCs is through Relay Ladder Logic or other easily learned language. 
• PLCs comes with program language built in its memory. 
• PLCs do not CONTAIN input and output devices such as keyboards, mouse, monitor, CD drives and other hard disks. It is in simple a self contained box with communication ports and set of terminals for input and output devices. Unlike computers which performs numerous tasks simultaneously, PLCs execute a single program in an orderly and sequential manner from first instruction to the last instruction PLCs have been designed for INSTALLATION and maintenance by plant electricians. Programming in PLCs is simple (Relay Ladder Programming), it does not include any advanced code. Troubleshooting is simpler and many PLCs are designed to include fault details and written fault details on display screen.

Programmable Logic Controllers (PLCs) have basic architecture compared to normal general purpose computers. A normal computer can be converted to PLCs by providing a way that the computer can able to receive information or signal from the field devices such as push buttons, switches and valve positions. Computer requires a some software to process the information obtained from the input to generate an output which decide whether to close or open the valve position in the process side.

Some of the important features and characteristics that distinguish between the general purpose computers and Programmable Logic Controllers(PLCs) are given below:

The sequential operation of the CONTROLLER that goes through the ladder diagram from top to bottom of the ladder. In this PROCESS it updates all the outputs corresponding to the INPUTS. SCAN takes place from left to right of each rung. Usually SCAN time is in MILLISECONDS and it is a continuous process.

The sequential operation of the controller that goes through the ladder diagram from top to bottom of the ladder. In this process it updates all the outputs corresponding to the inputs. SCAN takes place from left to right of each rung. Usually SCAN time is in milliseconds and it is a continuous process.

CPU is the brain of the SYSTEM and consists of 

• Microprocessor: To carryout arithematic and logical OPERATIONS.
• Memory: The area in the CPU in which the INFORMATION is stored and reterived.
• POWER Supply: The electrical supply that converts the ac voltage to various DC operating voltages.

CPU is the brain of the system and consists of 

The GENERAL language program consists of Ladder DIAGRAMS. Relay logic control SCHEME is represented in Ladder diagrams. ALTERNATIVE languages uses Boolean representation of these control schemes as base of the computer representation.

The general language program consists of Ladder Diagrams. Relay logic control scheme is represented in Ladder diagrams. Alternative languages uses Boolean representation of these control schemes as base of the computer representation.

PLCS are highly RELIABLE, easily programmable, Small and Inexpensive, PLCs can be designed with the COMMUNICATION capabilities so they can converse with the local or remote COMPUTER, They can sustain in robust environment less MAINTENANCE.

PLCs are highly reliable, easily programmable, Small and Inexpensive, PLCs can be designed with the communication capabilities so they can converse with the local or remote computer, They can sustain in robust environment less maintenance.

1. INPUT INTERFACE
2. MEMORY Section
3. Central PROCESSING Unit (CPU)
4. Programmable Language
5. Programming tool
6. An output Interface

1. Input Interface
2. Memory Section
3. Central Processing Unit (CPU)
4. Programmable Language
5. Programming tool
6. An output Interface

• DIGITAL input
• Digital Output
• Analog input 
• Analog output
• PULSE input
• COMMUNICATION MODULE
• CPU

• Sinking input / output provides a grounded CONNECTION to the load.
• SOURCING input / output provides to the load.

• COST of Hardware and Software
• Reliability FLEXIBILITY Scalability 
• Ease of database configuration 
• Graphics development
• Interlocks and batch processing
• Integration of high LEVEL APPLICATION

• Ladder logic
• FUNCTIONAL Block DIAGRAM
• Sequential FUNCTION CHART

• CPU
• The Input/Output INTERFACE SYSTEM