Intel 8085

Vss, also known as Gnd, is pin 20 on the 8085.

Interrupt handler is responsible for following functions:-

Determine the interrupt source.

Determine the service routine to serve the interrupt source.

An interrupt in the 8051 microcontroller is a mechanism that temporarily halts the execution of the main program to allow the processor to address an event or condition that requires immediate attention, such as a timer overflow, external signal, or serial communication. The 8051 supports multiple interrupt sources, including external interrupts (INT0 and INT1), timer interrupts (Timer 0 and Timer 1), and a serial communication interrupt. When an interrupt occurs, the microcontroller saves the current program state, jumps to a predefined interrupt service routine (ISR), and upon completion, resumes the original program. This allows for efficient handling of asynchronous events without continuous polling.

explain vector table?

It gets down syndrome.

It is a memory register inside the CPU. The function is to hold the current microinstruction. The microinstruction is the bits that drive the control signal and drive the data path.

In the 8085 microprocessor, the DAA (Decimal Adjust for Addition) instruction is used after an ADD instruction to convert the binary result of the addition into a Binary-Coded Decimal (BCD) format. Since the ADD operation works on binary numbers, the DAA corrects the result if the sum exceeds the BCD range (i.e., if any digit is greater than 9 or if there is a carry). This adjustment ensures that subsequent BCD operations yield correct results. Essentially, DAA makes the binary addition result suitable for display or further BCD processing.

Memory Read refers to the process when

1) HL pair holds the address which is to be read

2) this address is placed on address lines (ALE : Address Latch Enable, must be high at this moment)

3) then Memory Read Control Signal (MEMR) goes high to signify that at this moment we need to read (get) data from memory.

4) Then ALE goes low and data is placed on lower bit address lines ( Because data lines are multiplexed with lower byte address line)

5) After getting the data in the register, ALE again goes High, MEMR goes low.

Yes, a server is considered a special-purpose computer because it is designed specifically to manage network resources, store data, and provide services to other computers or clients over a network. Unlike general-purpose computers, which can perform a wide range of tasks, servers are optimized for tasks such as handling requests, data processing, and maintaining security and reliability. Their hardware and software configurations are tailored to meet the demands of serving multiple users simultaneously.

A 16 bit address bus can select 65536 locations.

increases speed

No. RST7.5 is a maskable interrupt on the 8085, not the 8086/8088.

7F

explain how slow memory get interfaced with 8085

A mnemonic could be used anywhere, not just microprocessors. It's a group of letters so you could remember the parts of something.

Example: MRS. NERG

Movement, Reproduction, Sensitivity, Nutrition, Excretion, Respiration and Growth.

This is a mnemonic for the characteristics of living organisms.

There are no instructions in the 8085 that execute in only one clock pulse. The minimum number of clock cycles is four; three for instruction fetch and one for instruction decode/execute.

Following facts determine the use of addressing bits of an instruction: Number of addressing modes: Sometimes an addressing mode can be indicated implicitly. In other cases, the addressing modes must be explicit, and one or more mode bits will be needed. Number of operands: Typical instructions on today's machines provide for two operands. Each operand address in the instruction might require its own mode indicator, or the use of a mode indicator could be limited to just one of the address fields. Register versus memory: The more that registers can be used for operand references, the fewer bits are needed. Number of register sets: One advantage of using multiple register sets is that, for a fixed number of registers, a functional split requires fewer bits to be used in the instruction. Address range: For addresses that reference memory, the range of addresses that can be referenced is related to the number of address bits. Because this imposes a severe limitation, direct addressing is rarely used. With displacement addressing, the range is opened up to the length of the address register. Address granularity: In a system with 16- or 32-bit words, an address can reference a word or a byte at the designer's choice. Byte addressing is convenient for character manipulation but requires, for a fixed-size memory, more address bits.

Internally two crystal oscillator cycles are used as one single cycle. During one single crystal cycle it is made to logic high and logic low in next cycle so, that 50% duty cycle is maintained.

indexed addressing

It may be any size, this register is use according to requirement of micro processor.

• If 8 or 16 bit data is required for executing the instruction present in register/register pair and named of register/register pair is given along the register.this instruction is called register addressing mode instruction.
• for example:
• MOV B,A

Food Stamps

A single board microcomputer is a microcomputer built on a single board. There are no plug-in boards required, though they might be optional. Most modern PC's are single board, if you ignore the fact that some of the parts, such as the RAM, are plugged in.

ALE

There are three fetch cycles in a three byte instruction. The first one is four clock cycles long, while the other two are three clock cycles long. Depending on what the instruction does, there will then be more read/write cycles.