Talk:Intel 8085

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[edit] Programming software

how can we program in 8085 microprocessors.

In the good-old-days you would start with 8085 datasheet, and paper and pencil.

Today the easiest way is to use some of the many 8085 simulators/emulators available on the net.

Take a look: type "8085 emulator" on Google. 8085 emulators/simulators are still quite popular as a teaching tool, so there are many (commercial) simulators/emulators available.

Here's couple of free emulators available:

Freeware simu&assembler

Freeware simulator

And if you want to use just an assembler:

ftp://ftp.simtel.net/pub/simtelnet/msdos/crossasm/ps85a12.zip

ftp://ftp.simtel.net/pub/simtelnet/msdos/crossasm/as80_130.zip

If you want to use some higher level language (eg. basic, pascal, c, java, ..) instead of assembler, someone else may give you more hints of free/cheap software.

Agreed, this should probably be separately provided in the form of a corresponding software section that provides lists of simulators and emulators for various platforms, preferably freely available stuff (open source and freeware).

BTW: the 8085 is also generally considered a spaceborne processor: http://klabs.org/DEI/Processor/index.htm —Preceding unsigned comment added by Parallelized (talk • contribs) 20:58, 28 January 2008 (UTC)

[edit] Using INTR signal

In reference to Nazli's correction "Comprehensive use of INTR requires..." which is commented "rudimentary use of INTR is possible even without an external Programmable Interrupt Controller".

I guess this refers eg. to using pullup resistors in AD0..AD7. Using this configuration, activating INTR causes the INTR recognition cycle to read FFh, which is the opcode of RST 7 instruction. So, with minimal components, you have created a system in which INTR signal is serviced as RST 7 instruction.

All this is interesting, but I fail to see if this clarification is worth the effort in short and generalized discussion of almost antique processor. Comments anyone?

I see your point - however the previous sentence:
"Use of the INTR requires an external Programmable Interrupt Controller such as an Intel 8259"
was factually incorrect. Maybe the whole discussion on interrupts needs to be abbreviated?
Nazli 05:47, 25 May 2006 (UTC)
You are right: facts are facts, and the use of "requires" is incorrect.
And reading the paragraph containing interrupts, I agree:
the discussion on interrupts should be abbreviated.
Perhaps, if we dump the references to pins, and condense the discussion
into one sentence?
All in all, I think the article is quite good.
It puts the 8085 in historical context, discusses historical facts, and
references details which have modern equivalents.
Maybe the article should be rewritten, but it isn't very long to begin with.
Omniwriter 14:52, 25 May 2006 (UTC)

Overall the article seems ok. The section on interrupts could possibly be shortened. One suggestion:

Old section:

"The microprocessor has three hardware based interrupt operations which are found in pins 7 through 9, these are called RST 7.5, RST 6.5, and RST 5.5 respectively. The 8085 has a TRAP interrupt which cannot be disabled (that is, TRAP is a Non-Maskable interrupt or NMI) and an INTR interrupt. Comprehensive use of the INTR requires an external Programmable Interrupt Controller such as an Intel 8259."

Proposed new section:

"The microprocessor has three hardware based interrupt operations as well as a TRAP interrupt which cannot be disabled (that is, a Non-Maskable interrupt or NMI) and an INTR interrupt."

Nazli 11:08, 26 May 2006 (UTC)

Your proposal is ok. Or how about this:
"The microprocessor has three maskable hardware interrupts (RST), one Non-Maskable hardware interrupt (TRAP), and
one externally serviced hardware interrupt (INTR)."
BTW, the articles on Non-Maskable Interrupts and 8259 are a way longer than this on 8085.
So, maybe this article could be longer and contain more details?
There are no details on opcodes of 8085.. What other aspects of 8085 are still missing?
Omniwriter 20:52, 26 May 2006 (UTC)

[edit] Clock Frequency

"The 8085 runs on a 6.14 MHz crystal, connected to X1 and X2 (pins 1 and 2)"

This is not strictly necessary is it? Only the max frequency is 6.14 MHz I believe? --Gingerjoos 03:35, 17 December 2006 (UTC)

[edit] CPU Architecture

The 8085 Architecture follows the von Neumann architecture, with a 16bit address bus, and a 8bit data bus. But it is actually based on harvard concept This abruptly ending sentence is confusing. What makes it based on Harvard-concept? Svofski 07:05, 9 July 2007 (UTC)

[edit] Commercial 8085 Simulators

I didn't add commercial/shareware simulators, because doing so might be disputable and be considered advertising, however maybe some folks are still interested, thus I put it here:

[edit] Shareware

[edit] Commercial