bit size

Discussion in 'General Electronics Chat' started by vead, Feb 24, 2014.

  1. vead

    Thread Starter Active Member

    Nov 24, 2011
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    mico controller has address bus, data bus, and control bus
    some word confusing me
    data path, data bus data size
    instruction path , instruction bus , instruction size
    Are they different or same things?
     
  2. t06afre

    AAC Fanatic!

    May 11, 2009
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    No they are not the same. As mentioned before. If you have none what so ever knowledge of microprocessor basics. It is very hard to help you. This forum can for sure teach you bits and bobs. But we can not replace a whole one-term course. Ask your teacher if he/she can recommend some books covering the basics of microprocessors. The school library may also be of some help I guess. Everyone has to learn to crawl before they can walk, and walk properly before they can run. To me it looks like you are trying to run before you even walk properly.
     
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  3. takao21203

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    Apr 28, 2012
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    Yes I recommended OP to read the 16F5X PDF- it is a simple controller.
    It has a block diagram, with all the paths drawn + their bit width.

    According to reply in other thread, OP is studying it right now.
     
  4. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    Horrible idea. It will only confuse the OP. OP needs to read or take a course on the basics as others have recommended. The OP first needs to have an understanding of basic microcrontolers before moving on to something as complex as a datasheet,
     
  5. MrChips

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    Oct 2, 2009
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    takao21203 and Metalmann like this.
  6. takao21203

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    I have learned microcontrollers with that, before of it, I did know 8086 assembler but it was more a black box to me. I did understand how it is manipulating the memory, but how and why and when exactly this happens electrically, was not so important.

    I did know CMOS circuits, but the bridge was just too wide.

    Also I learned C language the hard way- by meditating over the disassembly (which I was able to follow and understand). So I did see the effects of my typecasts, or the omission of the same (crash + reboot).
     
  7. tshuck

    Well-Known Member

    Oct 18, 2012
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    ...and by learning from the self-admitted "hard way", you are going to suggest the same for the OP?: confused:

    I just posted this link in the other rabbit hole thread, but it is relevant here too...
     
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  8. takao21203

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    It makes it much more unlikely to become thrown off with no idea what's wrong. Well in case of doubt, that IO port line has "latched", route to a different one...

    If a tutorial or programming book or manual is too technical, it becomes boring after a few pages, and hard to follow. I watched hours of videos how to do SMD soldering and I did not have a clue, but in the end, it can be explained in 6 or 7 lines with the right words.

    The 16F5x is confusing at the first look due to it's obscure banking, but if you understand how it works, you don't become confused so easily anymore- if at all. I found it helpful to spend time with it. There are no pheripherals (which in turn can be confusing).
     
  9. tshuck

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    Oct 18, 2012
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    Case and point. The OP doesn't understand how it works - that's the problem!
     
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  10. takao21203

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    We don't know the age group and we have so far not seen any actual work of OP.

    The document you linked are valueable but complex to read, there is even a danger in them, if people read them literallly or even memorize them, they become "little professors", able to recite a lot of facts faster than normal people can speak even.

    I like the approach using conventional language, with as little baggage for which you need a glossary as possible.

    I hope OP gets along somehow- from what I understand, there is a college project ongoing.

    And the main question seems to be, if "we" have an 8bit controller, is there a correlation to the number of control lines the decoder (for the opcodes) shall have?

    I tried to explain it kindof can be 8bit for some "controllers", but it only looks like it, and it could be 7 bit or 6 bit only internally.

    On paper, since opcode groups are made, the 68000 is only using 4 bits.

    It is like the total length of the coast of England. Of course on the map it has some determined length, but if you go into the small details, it gets longer and longer- indeed it is almost impossible to determine the "correct" length.

    It can be said to be "correct" for some purpose.

    If that purpose is not well understood, there is little hope to be able to measure the length correctly.
     
  11. tshuck

    Well-Known Member

    Oct 18, 2012
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    Engineering is a technical profession, requiring technical explanations and wording. There is no way around this if you ever intend to be an engineer.

    The OP's age had nothing to do with it. He doesn't understand the basics - just look at his previous threads from about a month ago asking about flip flops. It takes time to learn, and that's fine, but you must understand the basics to have any hope of understanding the applications and more complex theories.
     
  12. takao21203

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    Apr 28, 2012
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    I have skipped a few threads and posts without really reading it, and OP seems to be interested in digital logic, and particulary FPGA a lot.

    Engineering terminology is good for some people. Myself I am almost so "dyslexic" I can't even remember Ohms law. I would not make a good mathematican as such. But I do get along with maths when I use it in software. I made a QBASIC program which sorts points in a ring buffer, rotates it to change the colors on a circle, which in turn is bent so it looks like it is rotating. I ported it to VB6 some day...

    Without to look up the maths again, I can't remember after a few days.

    I never did learn the subject as such- maths, but I learned how to get along with it, if need be.

    Intelligence also can mean to understand HOW to apply information, and how to create CORRELATIONS of available information. It does NOT merely mean or describe the amount or complexity of information which is known or understood.


    Sure OP has taken the first step- asking questions.

    Learning HOW TO deal with information is in my opinion at least as important as to know the information itself.
     
  13. tshuck

    Well-Known Member

    Oct 18, 2012
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    Did I miss a post where someone asked about anything you just responded to?:confused:

    ...hence the thread...

    ...and part of how to deal with engineering information depends on your understanding of underlying theories and concepts.
     
  14. t06afre

    AAC Fanatic!

    May 11, 2009
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    I have to agree with Tshuck all the way here. Your advice in this matter have not been say very educational, but let me put it nice more on the obfuscation side. I can see that it has done in order to help, and respect that. But the problem is that you see things from your side only. Your advice lack a pedagogics thinking. And it is with that in mind Tshuck try to start his attempt to help.
     
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  15. takao21203

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    I have so far missed a report about a new insight or a progress, and taking a brief look at other threads of OP, I am also not too sure about these.

    Also the age does matter- if you talk to a 13 years old, they dont always prioritize.

    you can explain 20 pages about the bits for a decoder, it might be brilliant, and after that they'd just ask: "But why?"

    In order to help OP I think it can make sense to understand more about OP, and suggest something that can be done more easily, with progress visibly more quick.

    Maybe a small success story can be seen soon.

    Or in other words, I'd not give much about a rule about a correlation between data bus width, and opcode encoding bits- mostly I'd say there are so many things not understood properly I'd stop worrying about that for the time being.

    Or on the other hand, if you look on the internet for a z80 emulation core (as source code).

    Would you consider all people involved should keep it to the technical glossary very strict, and only answer questions asked? And not for instance ask, "But why?"

    Well in that case, it'd be my turn to do that...
     
  16. takao21203

    Distinguished Member

    Apr 28, 2012
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    Yes it could be I am selfish and self-righteous. Makes me think of that movie "Nobody Knows". It plays in a restaurant, You (a name), a woman maybe 45, tells her son, Akira, about 13, "You are boring", then in turn he answers "You are so selfish" (in that language it is not uttered "You"). Then she says "hurry up finish eating".

    Maybe both selfish.

    I mean, the information from Tshuck is there, and OP is free to make the best out of it. If that over the course of 200 threads is not taking place at all, there is more pedagogic thinking and skills required than most of us can provide at all.

    I am trying at least, without humilating OP. I am trying to figure out what OP is upto, and what is the problem, besides decoder bits.

    It has been explained, with some good links, and some bad? comments (from me), just saying, I get along, and I do understand about microcontrollers and opcodes.

    I tried to explain to OP, what materials and means of help and explanation I used over the years.

    Also I wanted to make clear it is not totally easy, like if OP understands now about the decoder bits, all is OK and construction of a microcontroller can take place.

    If the track record of OPs previous threads is similar, don't blame it on me.
     
  17. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    All you did was utterly confuse the OP in all of your threads which seems to be an on going theme.

    The poor OP has a great challenge with dealing in a complex subject in a language where he/she obviously has difficulty and you mention "chicken and the egg" in the one thread along with all kind of unrelated information.

    This OP needs simple instruction on the basics of CPUs. Others have done the right thing and tried to point the OP to some online resources. I just wish we knew of some resources in the OP's first language. All you did was to confuse the OP and possible scare him or her off.


    @OP please try to follow the links that the others have posted to teach basic CPUs and disregard the rest of this mess.
     
  18. WBahn

    Moderator

    Mar 31, 2012
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    One possibility that might be a good match for where the OP is at and what they are trying to learn is the Nand2Tetris project. A little bit about it can be found here.

    http://forum.allaboutcircuits.com/blog.php?b=590

    Since it is module, the OP can go a far as they want to and stop when they don't want to go further. But it should quickly get them introduced to the notion of bits and data paths and addresses and bus widths and such.
     
  19. takao21203

    Distinguished Member

    Apr 28, 2012
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    OMG.

    OMG.

    I wrote a long reply, then after considering, these replies make sense most.

    OP needs your help to consider it is a mess. OP will maybe express a Thank you.

    In the movie, some day Akira forges the signature of the mother for envelopes with money for Christmas. His sister askes him what he wants to buy with his money...

    Gyrokan! (baseball glove)

    Maybe I did not get the spelling right. But in baseball you have to be quick, the ball has 150 mph or the like.

    Speech wthout accentuation is a thing as such.
     
  20. tshuck

    Well-Known Member

    Oct 18, 2012
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    What are you on (or should be)?
     
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