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An instruction fetch in the 8085 is similar to an operand fetch...
During T1, ALE pulses high for one half cycle. On the falling edge, external logic is expected to strobe the AD0-AD7 lines to form the A0-A7 lines. A8-A15, IO/M-, S0, and S1 are also presented, but they stay valid after ALE. S0 is high for opcode fetch, and low for operand fetch. RD- goes true (low) at the end of T1.
If READY is false at the end of T1, TWAIT is entered, and all lines are persisted, with TWAIT repeated as necessary until READY is true.
At the end of T2, the CPU strobes the data presented on AD0-AD7 by external logic.
At the midpoint of T3, RD- goes false (high) and the external logic must stop driving AD0-AD7.
T4 is used to decode and process the opcode. External logic does nothing, since there is no ALE.
If the opcode requires extra data, such as immediate data or an address, T1, TWAIT, T2, and T3 are repeated to fetch the additional bytes, although S0 is low during these cycles.
What else can I help you with?
How many instruction are there in 8085 mp?
There are 74 instructions in the 8085 microprocessor.
What is STA 3000H in microprocessor?
STA 3000H is an 8085 instruction that says to store the accumulator at memory location 3000H.
Timming diagram for lda instruction in microprocessor 8085?
The timing diagram for the LDA (Load Accumulator Direct) instruction in the 8085 microprocessor involves several key phases. Initially, the opcode is fetched from memory, which takes 4 clock cycles. Next, the address of the data to be loaded into the accumulator is specified in the next two cycles, followed by another two cycles to read the data from the specified memory location into the accumulator. The entire process typically takes 7 machine cycles, including the necessary memory access time.
What is NOP Instruction stands in 8085 microprocessor?
The NOP instruction is a no-operation instruction. It does nothing to the state of the machine, except to use some time. In the case of the 8085, it uses four clock cycles plus however many wait states are need to access the NOP instruction from memory.
What is signal in microprocessor 8085?
In the 8085 microprocessor, a signal refers to an electrical voltage or pulse that conveys information between the microprocessor and other components in the system, such as memory and input/output devices. These signals include control signals, address signals, and data signals, which coordinate operations like data transfer, memory access, and instruction execution. The 8085 uses a combination of these signals to ensure proper communication and functionality within the microprocessor architecture.
How does the 8085 microprocessor instruction register work?
stores next instructions
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 many memory location can be addressed by microprocessor 8085?
The 8085 can address 216, or 65536 different memory locations.
Why is the jump instruction jmp of 8085 microprocessor given the immediate addressing mode?
because the operand is available in the instruction itself
How many location can be accessed by 8085 microprocessor?
The 8085 microprocessor can access 65536 (2^16) locations in memory, and 256 (2^8) locations in I/O space.
What is the purpose of the RRC instruction in 8085 microprocessor?
We can implement "Divided by '2' " operation by using RRC.
How do you draw timing diagram for 8085 microprocessor instruction?
Refer http://wiki.answers.com/Q/How_to_draw_timing_diagram_for_8085_microprocessor_instruction
