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In the general case, a bus is tristated to allow more than one source to drive it. This can be the simple case of a bi-directional bus, or the more complex case of a multi-master bus configuration.
In the 8085, the address bus is tristated when a HOLD/HLDA sequence is in process, allowing another bus master to control the bus. The data bus is tristated for the same reason, and also to allow bi-directional data flow (read vs write) to occur.
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What is bus in 8085?
there are mainly 3 buses are there in 8085. They are: Address bus :-Used to carry address Data bus :- Used to carry data Control bus :-Used to carry signals such as control and timing signals
What is microprocesser 8085?
microprocessor 8085 is basic 8 bit microprocessor by Intel Corp. it has 64Kb memory and 16 address buses and 8 data buses it has 40 pin ic. 8 address and 8 data buses are multiplexed with each other for reducing the total number of pins from the microprocessor 8085 . it require 5MHz clock frequency for operation. only a crystal which connected easily across two pins of microprocessor can provide this clock.
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
How are the data bus and address bus are demultiplexed?
The data and address buses are multiplexed in order to save pin count on the chip. In the first clock cycle of a read or write cycle, the address is emitted on the address/data bus. The ALE signal is used to strobe the address, after which the address/data bus becomes the data bus. External logic is expected to strobe the address at the trailing edge of ALE. ALE is generated directly by the 8085, and by the 8086/8088 in minimum mode. In maximum mode in the 8086/8088, ALE is generated by the 8288 Bus Controller.
Why are the buffers often needed on the address and data and control buses in a microcomputer system?
Buffer is a logic circuit that amplifies current or power.It is used in address and data buses to increase their driving capability.
What is the data size in Intel 8085?
The data size in the 8085 is 8 bits.
What type of buses do you find on the mother board?
address bus, data bus
Draw a schemetic to demultiplex bus ad0-ad7 using any octal latch in 8085 microprocessor?
The 8085 microprocessor is used IC 74LS373 to latch the address of 8085. Basically latch is consists of 8 flip flops. Generally we used D-flip flops (Delay).The clock of these flip flops are connected together and available as a output pin called enable.Working : The address will appear on AD0 AD7 lines. The ALE will go high and forcingEnable = 1. This will make latch enable and ready to work. Before address disappears ALE = 0. This will make latch disable. AD0 - AD7 will now be used as data bus.Hence, AD0 - AD7 (low order) address bus of the 8085 microprocessor is multiplexed (time-shared) with the data bus. The buses need to be demultiplexed.
Why is data bus bidirectional but address bus unidirectional?
The address bus is unidirectional becos address information is always given by microprocessor to i/o devices. The data bus is bidirectional bcos it takes the data from other devices & also give the data to other i/o devices
Why higher order address bus not multiplexed with data bus of 8085?
The higher order address bus is not multiplexed with data bus of 8085 because that is the way Intel designed the processor. Besides, the data bus is only 8 bits and the address bus is 16 bits. If you were to multiplex the whole address bus on the data bus, you would need two T1 (ALE) states, and that would be excess logic. Back to the original answer - that is simply the way Intel designed the processor.
What is the difference between the Intel 8085 and the Intel 8086?
The Intel 8085 is an 8 bit microprocessor created in 1977.The Intel 8086 is a 16 bit microprocessor created in 1978. The 8086 was the first chip to start the x86 architecture family.8085 contains 16-bit address bus and 8-bit data bus8086 contains 20-bit address bus and 16-bit data bus..In 8085 the clock speed is 3MHZwhere as in 8086 the clock speed is 5MHZ.there are two differences btw 8085&80861. 8086 has 6 byte queue but 8085 has 4 byte queue2. 8086 has 16 bit data bus where as 8085 has 8 bit data bus
What is the addressing mode of the instruction PCHL in 8085 microprocessor?
It is register addressing mode, as it moves the content of HL to PC which is data and not address.
