Questions tagged [8085]

An eight bit microprocessor made by Intel in 1976.

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How to reset all flags in 8085 without an arithmetic or logic operation?

How can I reset all flags in 8085 without an arithmetic or logic operation?
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1answer
775 views

In 8085, what is peripheral mapped I/O?

Is the peripheral mapped I/O different from what is known as port-mapped I/O or simply known as I/O mapped I/O? I don't see the usage of the term "peripheral mapped I/O" around much. Was it only ...
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1answer
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How to set flags in microprocessor 8085 after IN instruction?

When microprocessor reads an input port, the instruction IN does not set any flag. If the input reading is zero, what logic instruction can be used to set the ZERO flag without affecting the contents ...
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1answer
623 views

Programming an EPROM using 8085 kit

I need to program an EPROM/EEPROM with the code for an 8085. I do not have a programmer. I can't buy one. But I have access to an 8085 kit. Can I use it to program the EPROM/EEPROM via an interface? ...
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1answer
599 views

Identification of hardware interrupts in microprocessor 8085

I am familiar with the RIM and SIM instructions that are available in the instruction set of microprocessor 8085. And thus I can enable RST 7.5 and RST 6.5 interrupts using SIM instruction and EI ...
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1answer
25k views

Number of machine cycles in microprocessor 8085

The DCR instruction in MP 8085 has has 1 machine cycle, i.e. opcode fetch cycle. But the DCR M instruction has 3 machine cycles. What are those three machine cycles?
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4answers
5k views

Memory mapping in the 8085 microprocessor

In the 8085 microprocessor there is 64 kb of memory available of which some are assigned to ROM while others are assigned to RAM. My question is, why is ROM always mapped to a lower region of memory ...
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2answers
7k views

A program to add 6 bytes of data and store sum and carry in 8085 instruction set

I have a question on 8085 instruction set. A program to add 6 bytes of data stored in memory starting from 4500h. must use b register to save any carries and finally store the sum and carry at two ...
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3answers
12k views

How to set all flags in 8085?

My Microprocessor teacher of 8085 gave an assignment to set all flags ! I have written this little program to set all except Sign, Please help me out ...
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2answers
23k views

Why in HL pair, H is stored after L register

Why in 8085, during LHLD and SHLD instructions L is used first while in BC and ...
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0answers
2k views

Regarding 8085 DAD timing diagram

Can anybody tell me about DAD instruction in 8085. Is ALE high twice in first machine cycle of DAD instruction. Can anybody suggested me timing diagram of DAD and HLT instruction.(Any other link)
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2answers
196 views

Why the time of execution is never shown in any Instruction Cycle?

In case of timing diagrams of 8085, what I saw is that, always Opcode Fetch, Memory Read/Write, IO Read/Write is shown but execution is never shown. Is it because the execution time is too less ...
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1answer
2k views

Using BSR Mode of 8255 with 8085

When using the 8255 to glow an LED array using BSR mode, is it necessary to first set port c as an output port? Why? In our lab, when I had not not set port C as output and directly used BSR mode to ...
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2answers
3k views

8085 Memory address decoding with a NAND Gate

I have a problem for homework that has me stumped. Basically, what I'm given is 2 R/WMs, each 2048 bytes * 4. Connected to each of their CS pin is a NAND gate with pins A12-A15 connected from the 8085 ...
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4answers
10k views

what does byte 2 and byte 3 mean?

An instruction from the instruction set of intel 8085 that is SBI data (Subtract immediate with borrow) . This instruction says "The contents of the second byte of the instruction and the contents of ...
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4answers
144k views

What does edge triggered and level triggered mean?

I am studying 8085 microprocessor architecture and the word edge triggered and level triggered confusing me really very much. Can anyone explain me it in layman's words ? While studying the ...
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1answer
504 views

Learning about the Interrupt system of the 8085 processor

I am trying to investigate the RST5.5, RST6.5, and RST7.5 interrupts on the 8085 microprocessor. I want to find information about the to the type of interrupting signal used and the built in ...
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3answers
6k views

Reading/Writing a usb flash drive

I wish to expose a usb flash drive and read it as raw binary data, particularly read each byte & simultaneously writing it to another flash drive. Given that I am working with an 8085 ...
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5answers
39k views

Why in 8085 microprocessor, the clock frequency is divided by two?

Why is it that the produced clock frequency is 6.144 MHz, but internally it (8085 processor) uses only 3.072 MHz. Also what leads to the specific value of 6.144 in a clock. I found an answer at ...

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