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How to Start hardware of 8085up......??

Note the case of the letter used: "b" = bits; "B" = bytes. 64Kb = 8KB. 2864 = 64Kb = 8KB.
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I will always remember this.....
thanks

I don't understand the rest of your question, sorry.
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as we will connect add. pins of 8085 to ROM directly but in case of RAM there will be no data left after switching off power, so how it work in circuit we will connect it than how it will do task....??
I hope know you will be able to understand my question....
 
RITESH said:
as we will connect add. pins of 8085 to ROM directly but in case of RAM there will be no data left after switching off power, so how it work in circuit we will connect it than how it will do task....??
I hope know you will be able to understand my question....
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You also connect the address pins of the 8085 to RAM also--I thought this was clear.

If you need static data to be in RAM, you need to program a routine to move it from ROM into RAM.
 
Chuck(G) said:
If you need static data to be in RAM, you need to program a routine to move it from ROM into RAM.
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Just to make clear, with this setup there is no speed difference between RAM and ROM. Code that runs out of ROM will be no faster than code stored in RAM. The previous mention that code is usually executed from RAM for speed only applies when the RAM is faster than your code storage device.
 
I think here should be 64Kb not 64KB or 8KB.........
is this correct??
 

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No, the datasheet is correct. The 8080 and 8085 can address 65 536 bytes (524 288 bytes), address range of 0000h - FFFFh.

You're just using part of the addressing range.
 
No, the datasheet is correct. The 8080 and 8085 can address 65 536 bytes (524 288 bytes), address range of 0000h - FFFFh.
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OK, i have seen 2864 data sheet it was 64kbits of EEPROM....
That mean 8085 is 64Kbytes and this ROM is 64Kbits so, we can increase its ROM more, can we.........??
 
Go back to what I said in #118 of this thread. I noted that it would be simple to substitute for the 2864, an M28256 (32KB/256Kb) EEPROM. As long as we're dividing our address space in the middle (32KB ROM, 32KB RAM), you can substitute a 62256 SRAM for the RAM on your system. That way, you have 32KB ROM from 0000h-7FFFH and 32KB RAM from 8000h-FFFFh.

That fills the memory address space of the 8085. Dividing the memory space un-equally (for example, 48K ROM and 16K RAM) would take more logic.
 
OK, Now i am getting you...
as your are saying to divide memory space in equal half due to which uP will run faster and small logic circuits are needed....but in our computer we have few GB of RAM and hard disk is very big in space so, how it work.......
 
That's beyond what I'm willing to discuss. Suffice it to say that the idea of "virtual memory" has been around a very long time. Modern CPUs are far more complex--the newer CPUs have close to a billion (10**9) transistors on them; the 8085 had 6,500.

Software has become bloated over the years. Old systems tended to be far more efficient with memory use. The IBM System/360 could run DOS/360 in an 8KB partition, for example. A 64K IBM System/360 Model 40 was very typical for medium-sized mainframes of the time.
 
Now please tell what to do??
As my EEPROM programmer is working well............
 
OK, First which program to add.??
and at starting adds. is there any need of adding any secret codes??
and pleas tell name of chip i want to buy and whichcrystal to have??
 
You won't need any secret codes unless you put an Intel CRM 80114 discriminator IC on the address bus between the 8085 and RAM, which is unnecessary in most cases. (You usually only find them in military hardware or the process control equipment used in water fluoridation plants.)
 
Where to get it data sheet i am not getting it.!!!
We can't use 8085 without this chip??
 
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