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Intel 8085
Introduced by Intel in 1977, the Intel 8085 is an 8-bit microprocessor that is binary-compatible with Intel 8080. It only requires a +5-volt power supply and has been used as a microcontroller.
1,493 Questions
What is the clock speed of 8085 mp?
The clock speed of the 8085 depends on the particular chip chosen. The basic 8085 could run up to around 3 MHz. The -1 version could run up to around 6 MHz. The -2 version could run up to around 5 MHz.
In each case, the crystal frequency had to be exactly twice the desired clock frequency, i.e. 6 Mhz, 12 MHz, and 10 MHz, respectively.
In all cases, the minimum clock frequency was 500 KHz. (Crystal 1 MHz)
Address Latch Enable:-
Address Latch was Intel's way of limiting the number of pins on their early microprocessors, to limit the production cost.
Sadly this "feature" remained in Intel processor architecture for several generations, despite the fact that production cost was no longer an issue.
What it does: On the early processors there was an 8 bit bus acting both as an address and a data bus (to save pins). Then there was the ALE (Address Latch Enable) pin, that determined if the bus should act as data or address bus. This of course decreased the efficiency of the processor, because you had to switch back and forth between the two states, according to which bus was needed.
How many bits of address bus are required to address 1mb memory?
You need 20 bits of address bus to address 1 Mb of memory.
How many machine cycles are required for SHLD in 8085?
The SHLD instruction in the 8085 requires 6 (opcode, decode, and increment) + 3 (low address fetch) + 3 (high address fetch) + 3 (low, L, store) + 3 (high, H, store) cycles which equals 18 cycles, not including wait states.
Why all the 16 address lines are not act as a data lines in 8085 microprocessor?
the 8085 microprocessor is a 8-bit microprocessor and these are bidirectional but the address lines are unidirectional.these address lines are used to address the location of the instruction in memory .these data lines are used to transfer data between processor and peripheral devices. when the address of the instruction will be recognized by the address lines the data will be send to the processor
therefore the 16 address lines are not act as a data lines in 8085
Who invented the microprocessor first and what was the first microprocessor?
Ted hughes was the first person who designed microprocessors.
In 1971 Ted hughes make first microprocessor for intel.
The name of the first microprocessor was:
Intel-4004.
It contains lacs of electronic circuits.
What is a direct address in language?
It means speaking to someone directly. Susan, clean up your room. Bob, hand me a flashlight. I told you already, Mom, I am not going. In these sentences, the direct address is to Susan, Bob, and Mom.
What is the difference between Instructions decode and register fetch?
Instruction register is use to store the next instruction to be executed.
Instruction decoder is use to decode the instruction come from the memory and tell the CPU what is instruction really are. (CPU interpret instruction is different from the data store in the memory . A good example is , memory can store hexadecimal, but device only can read binary data.) without decoder the device cannot indicate or recognize the data )
Distinction
"memory can store hexadecimal, but device only can read binary data" This is an improperly worded, misleading statement. The difference between binary and hexadecimal is purely interpretive. Reading hexadecimal is a function of dividing the bits into groups of 4 and assigning a unique symbol to the pattern; 0-9 + A-F. This is only translating from one numbering system to another. The memory isn't specifically able to store hexadecimal as opposed to binary; it stores a BYTE as a group of EIGHT BITS no matter what. So even if the hardware is designed to move 64 bits at a time, grouping the bits into nibbles of four bits is how we interpret the bit pattern in hexadecimal.
Another Answer <<< Truth!
Instruction Register is where the instruction bit pattern is loaded for execution. Instruction Decoder is all the hardware logic that is cascade triggered by the instruction bit pattern during execution.
What action is taken when the processor under execution is interrupted by TRAP in 8085MPU?
Processor serves the interrupt request after completing the execution of the current instruction.
An interrupt is a signal from hardware (h/w interrupt) or software (s/w interrupt) to indicate the occurence of an event. It indicates the need of a change in execution. Interrupt handling or servicing of the interrupts depends upon the design of the operating system. A routine which will be called for servicing the interrupt is known as interrupt service routine or ISR and the request for the ISR through an interrupt is known as interrupt request or IRQ. Interrupt is a mechanism used for implementing the multitasking concept. It will use the concept of context switching, for servicing the request.
A memory mapped register is a register that has its specific address stored in a known memory location.
What did the message on the stone promise to whomever carried out its instruction instruction?
"The Two Brothers"
Leo Tolstoy
Two brothers set out on a journey together. At noon they lay down in a forest to rest. When they woke up they saw a stone lying next to them. There was something written on the stone, and they tried to make out what it was.
"Whoever finds this stone," they read, "let him go straight into the forest at sunrise. In the forest a river will appear; let him swim across the river to the other side. There he will find a she-bear and her cubs. Let him take the cubs from her and run up the mountain with them, without once looking back. On the top of the mountain he will see a house, and in that house will he find happiness."
When they had read what was written on the stone, the younger brother said: "Let us go together. We can swim across the river, carry off the bear cubs, take them to the house on the mountain, and together find happiness."
"I am not going into the forest after bear cubs," said the elder brother, "and I advise you not to go. In the first place, no one can know whether what is written on this stone is the truth--perhaps it was written in jest.
In the second place, even if what is written here is the truth--suppose we go into the forest and night comes, and we cannot find the river. We shall be lost. And if we do find the river, how are we going to swim across it? It may be broad and swift.
In the third place, even if we swim across the river, do you think it is an easy thing to take her cubs away from a she-bear? She will seize us, and, instead of finding happiness, we shall perish, and all for nothing.
In the fourth place, even if we succeeded in carrying off the bear cubs, we could not run up a mountain without stopping to rest.
And, most important of all, the stone does not tell us what kind of happiness we should find in that house. It may be that the happiness awaiting us there is not at all the sort of happiness we would want."
"In my opinion," said the younger brother, "you are wrong. What is written on the stone could not have been put there without reason. And it is all perfectly clear. In the first place, no harm will come to us if we try. In the second place, if we do not go, someone else will read the inscription on the stone and find happiness, and we shall have lost it all. In the third place: if you do not make an effort and try hard, nothing in the world will succeed. In the fourth place: I should not want it thought that I was afraid of anything."
The elder brother answered him by saying: "The proverb says: 'In seeking great happiness small pleasures may be lost.' And also: 'A bird in the hand is worth two in the bush.'"
The younger brother replied: "I have heard: 'He who is afraid of the leaves must not go into the forest.' And also: 'Beneath a stone no water flows.'" Then the younger brother set off, and the elder remained behind. No sooner had the younger brother gone into the forest than he found the river, swam across it, and there on the other side was the she-bear, fast asleep. He took her cubs, and ran up the mountain without looking back. When he reached the top of the mountain the people came out to meet him with a carriage to take him into the city, where they made him their king.
He ruled for five years. In the sixth year, another king, who was stronger than he, waged war against him. The city was conquered, and he was driven out. Again the younger brother became a wanderer, and he arrived one day at the house of the elder brother. The elder brother was living in a village and had grown neither rich nor poor. The two brothers rejoiced at seeing each other, and at once began telling of all that had happened to them.
"You see," said the elder brother, "I was right. Here I have lived quietly and well, while you, though you may have been a king, have seen a great deal of trouble."
"I do not regret having gone into the forest and up the mountain," replied the younger brother. "I may have nothing now, but I shall always have something to remember, while you have no memories at all."
Difference between two address instruction and one address instruction?
Two address instructions use registers as operand locations.
Example of a half word length (16 bit) Two address format.
Bits 0-3 OP-Code bits (4 bits 16 different Mnemonics).
Bit 4 instruction type ( e.g. 0 means half word length).
Bit 5 fixed at value 1 used as extension to op-codes.
Bits 6-9 Address A (4 bits refers to a registers hence a total of 16 registers).
Bits 10-11 addressing modes ( 2 bits hence 4 different addressing modes in this case).
Bits 12-15 Address B (4 bits refers to a registers hence a total of 16 registers).
If 16 OP-codes for One address instructions is to be: ADD, ADC, SUB, SBC, XOR, BIT, CMP, INC, DEC, LDA, STA, AND, OR, JMP, BRN, JSR.
For Two address instructions the following 6 OP-Codes are dropped: INC, DEC, STA, BRN, JMP, JSR, but new OP-Codes with the help of bit #5 is introduced instead
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now let's to introducing
One Address Instructions
This is for a 32 bit CPU word length.
Bits 0-3 OP Code bits (4 bits 16 different OP Codes).
Bit 4 word length (0/1 Two different length 16 or 32 bit in this case).
Bits 5-7 Addressing Modes (3 bits 8 different Addressing Modes).
Bits 8-31 # of Addresses (2^24 Addressing Options).
The possible OP-Codes could be: ADD, SUB, ADC, SBC, AND, XOR, ORA, BIT, CMP, LDA, STA, INC, DEC, BRN, JSR, JMP.
one addressing
24 bit Address
3 bit AM
1/0
OP Code
two addressing
0000
00
1111
1
0
0010
What is an 16 bit microprocessor?
In computer architecture, 32-bit integers, memory addresses, or other data units are those that are at most 32 bits (4 octets) wide. Also, 32-bit CPU and ALU architecturesare those that are based on registers, address buses, or data buses of that size. 32-bitis also a term given to a generation of computers in which 32-bit processors were the norm.
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295 or −2,147,483,648 through 2,147,483,647 using two's complement encoding. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressablememory.
The external address and data buses are often wider than 32 bits but both of these are stored and manipulated internally in the processor as 32-bit quantities. For example, the Pentium Pro processor is a 32-bit machine, but the external address bus is 36 bits wide, and the external data bus is 64 bits wide.
32-bit - Computers or software programs capable of transferring data 32-bits at a time. Examples of 32-bit operating systems are OS/2 and Windows NT. The first true 32-bit processor was the Intel 80386. 32-bit can also refer to the amount of colours a video card is displaying. 32-bit is the same as 16.7 million colours (24 bit colour with a 8-bit alpha channel).
Compare 8086 microprocessors and 8088 microprocessors?
S.No.8086 Microprocessor8088 Microprocessor1The instruction Queue is 6 byte long.
The instruction Queue is 4 byte long.
2In 8086 memory divides into two banks, up to 1,048,576 bytes.
The memory in 8088 does not divide in to two banks as 8086.
3The data bus of 8086 is 16-bit wide
The data bus of 8088 is 8-bit wide.
4It has BHE( bar ) signal on pin no. 34 & there is no SSO(bar) signal.
It does not has BHE( bar ) signal on pin no. 34 & has only SSO(bar) signal. It has no S7 pin.
5The output signal is used to select memory or I/O at M/IO(bar) but if IO(bar)/M low or logic '0' it selects I/O devices and if IO(bar)/M is high or logic '1'it selects memory.The output signal is used to select memory or I/O at M(bar)/IO but if IO/M(bar) is low or at logic '0',it selects Memory devices and if IO/M(bar) is high or at logic '1'it selects I/O.6It needs one machine cycle to R/W signal if it is at even location otherwise it needs two.
It needs one machine cycle to R/W signal if it is at even location otherwise it needs two.
In 8086, all address & data Buses are multiplexed.
In 8088, address bus, AD7- AD0 buses are multiplexed.
It needs two IC 74343 for de-multiplexing AD0-AD19.
It needs one IC 74343 for de-multiplexing AD0-AD7.
How many registers are there in an 8085 microprocessor?
Accumulator or A register is an 8-bit register used for arithmetic, logic, I/O and load/store operations. Flag is an 8-bit register containing 5 1-bit flags: * Sign - set if the most significant bit of the result is set. * Zero - set if the result is zero. * Auxiliary carry - set if there was a carry out from bit 3 to bit 4 of the result. * Parity - set if the parity (the number of set bits in the result) is even. * Carry - set if there was a carry during addition, or borrow during subtraction/comparison. General registers: * 8-bit B and 8-bit C registers can be used as one 16-bit BC register pair. When used as a pair the C register contains low-order byte. Some instructions may use BC register as a data pointer. * 8-bit D and 8-bit E registers can be used as one 16-bit DE register pair. When used as a pair the E register contains low-order byte. Some instructions may use DE register as a data pointer. * 8-bit H and 8-bit L registers can be used as one 16-bit HL register pair. When used as a pair the L register contains low-order byte. HL register usually contains a data pointer used to reference memory addresses. Stack pointer is a 16 bit register. This register is always incremented/decremented by 2. Program counter is a 16-bit register.
What is the memory write operation?
read/write permissions/privileges allow the user to read, append and delete records from your database tables, however it cannot alter / create / drop the tables and its structures.
Read/write privileges are ideal for forums and production websites that don't require creation or alteration of table structures on its normal operations.
How many nuMBer of address lines required for 8 MB of memory?
It takes 23 address lines to address 8 mb of memory.
Data transfer schemes in Microprocessor :-
Data can be transferred between memory, microprocessor and input output devices. the speed and format of all the input output devices does not matches microprocessor.For example some input output devices like ABC' and DAC's are slow as compared to microprocessor.Some devices are serial in nature while microprocessor is parellal in nature.Because of this, number of data transfer schemes have been devided to cope with this problem.The data transfer schemes can be broadly clasified into two categories :-
What are the kinds of microprocessors?
A microprocessor is a chip that serves as the central processing unit (CPU) in personal computer(PCs). it is often called a logic chip or master chip. it controls all programs and performs arithmetic calculations with great accuracy. it acts as the 'brain' of the computer.
example:-
Intel 4004 , Intel 8080 , Intel Pentium Pro , Pentium Microprocessor.
How much virtual memory can be address with 16 bit address bus?
You can address 2^20 (or 1,048,576) locations. Each location will consist of 16 bits (1 or 0) which is commonly called a Word (though that isn't always the case).
I think what you're really looking for is the answer in bytes. Each data bus line holds a bit, 8 bits is a byte, so you're data line is 2 bytes. Since each location holds two bytes, this would be 2,097,152 bytes, or 2MB
How does microprocessor differentiate between data and instruction code?
i) Instruction code deals only with mnemonics and its corresponding opcode but data code refers to your data like 10h which is always of 8 bits or a particular address say 8080h which is of 16 bits.
ii) Data is your input to the instruction but an opcode is native to your machine.
iii) Data is user specific instruction while opcode is machine specific instruction
iv) You can alter data code but you cannot modify an instruction opcode.
