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What is the need of ale signal in 8085?
The ALE signal on the 8085 is Address Latch Enable. When ALE is true, the data bus contains the low order address information for the current bus cycle. External hardware, i.e. latches, are expected to follow the data bus when ALE is true. At the point where ALE goes false, at approximately the rising edge of CLK, the latches are expected to latch and hold the data bus, presenting it to the outside world as the low order address bus.
What is basic control signal used in 8085?
The control signals in an 8085 are already generated. They are CLK, S0, S1, ALE, RD-, WR-, IO/M-, INTA-, HLDA, SOD, and RESET OUT. The only control signal that needs to be generated in a medium to large bus organization is DATAENEABLE-. This is optional, if the external logic is compatible but, if not, it needs to be generated from ALE, S1, and CLK, in order to properly drive the data bus buffers without encountering a race condition during WR-. Basically, DATAENABLE- is equal to (RD- when ALE is low) if S1 is high, and it is equal to ALE if S1 is low.
What is ALE in 8085 in microprocessor?
ALE=Address Latch Enabled.(pin number 30 in 8085)8085 has a special pin referred as ALE, which indicates whether multiplex bus functions as an address bus or a data bus. Whenever 8085 starts any new operation, ALE signal goes to logic 1 for about 1/2 clock cycle, at about the falling edge of CLK. If ALE=1 then multiplex bus functions as address bus. After that half clock cycle, it goes to logic 0 for nearly 3 or 4 clock cycles. If ALE=0 then multiplex bus acts as a data bus.The ALE pin helps to enable the latching of lower order ADDR bus. The AD0-AD7 pins, as well as other control pins such as S0, S1, IO/M-, and the other address pins A8-A15, are setup to be correct at the falling edge of ALE.
A positive going pulse which is always generated when 8085 MPU begins the machine cycle?
ALE Address Latch Enable
What does the ALE signals represent?
ALE signals means 'address latch enable' .If its value is 1,it enable the latch but doesn't store. and when its value is 0 it store the contents of latch.
Difference between 8080 and 8085?
The 8085 has a single +5V power supplyThe 8085 has a multiplexed low order address busThe 8085 has extra single pin interrupts, TRAP, RST7.5, RST6.5, and RST5.5The 8085 has serial I/O pins SID and SODThe 8085 has maskable interrupts and the RIM/SIM instructionThe 8085 includes the functionality of the 8224 clock genereator and 8228 system controllerThe 8085 added several 16 bit operations
How much ale does a 'traditional yard of ale hold'?
2 imp pint = 1,14L
T state in op-code fetch of 8085?
There are four T states during op-code fetch in the 8085. T1 is the ALE state, where the address is emitted and the RD- line goes true; TWAIT is zero or more wait states based on READY; T2 is the middle of the fetch, and the internal strobing of the op-code; T3 is the completion of the fetch and stabilization of the bus signals; and T4 is the internal processing cycle.
When trap interrupt line is checked by 8085 microprocessor?
In the 8085, trap, intr, and rstx.5 lines are checked on the falling edge of clock, at the beginning of the last T cycle of an instruction, or approximately one clock cycle before ALE.
What is the function of IN in 8085?
ALE is a signal that means that the data bus contains the lower order address bus values. External hardware should strobe the data bus during ALE time, and lock it on the falling edge of ALE.
Why clock signal is not a perfect square wave in the 8085 timing diagram?
(Except for my discussion of ALE, below, I was not aware that the clock signal in the 8085 microprocessor was not perfectly square, but in my designs using the 8085 it did not matter, as I always made sure the hardware design always met the correct setup and hold times. This answer is intuitive, rather than being based on internal design knowledge.) In order to maximize clock speed, and resulting processor performance, Intel designed internal delays into various aspects of the 8085 design. Since these delays were not symmetrical for each edge of the clock, the resulting clock is not square, even though it is stated that clock is one half of the oscillator frequency. (As far as ALE is concerned, I was aware that ALE became true about one sixth of a clock after the falling edge of clock, and persisted for about one half clock. This does not line up with clock or with the oscillator running at twice clock, so it is obvious that there are internal delays built in. All I knew was that the rising edge of clock following ALE occured during ALE, and that the status lines and high address bus changed state about one sixth clock after the beginning of ALE, so I took this into account when I designed my bus control logic.)
How is demultiplexing done in 8085 microprocessor?
it is nothing
