Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: Bert on January 05, 2012, 12:40:38 PM
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This is perhaps not the right place to ask this but I thought I'd try. I understand what a transistor is and how it works, but how do a bunch of transistors together enable logic to 'happen'? I want to be able to wrap my head around what is physically occurring in a microprocessor. I don't intend to try this, but in theory, how would one actually go about making a simple microprocessing circuit?
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Hi Bert,
You can always start by performing Google (http://www.google.co.uk/search?hl=en&source=hp&q=how+microprocessors+work&gbv=2&oq=how+microprocess&aq=0&aqi=g10&aql=&gs_sm=e&gs_upl=967l4212l0l5008l16l16l0l5l5l0l187l1339l5.6l11l0) search :)
If You understand how transistors work, then You probably know that using transistors it is possible to build logic gates: AND, OR, NOT, XOR. With one gate You can perform 1-bit operation, there You have simplest binary calculator. Increase complexity and You get 8-bit calculator.
Finally, have a look at video below (You can try to recreate it with Phun (http://www.algodoo.com/wiki/Download) simulator if it's still free of charge) imagine that latches are replaced by transistor circuits and paths are PCB tracks, there You have it :)
Giant Digi-Comp II (http://youtu.be/fLuvopVjAWg)
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There is no logic per say programmed into processors. A processor is just a filter of sorts which takes instructions from you, closes the gates you tell it to, then processes the commands you gave it.
(http://static.ddmcdn.com/gif/microprocessor1.gif)
http://computer.howstuffworks.com/microprocessor2.htm (http://computer.howstuffworks.com/microprocessor2.htm)
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I recommend this: http://www1.idc.ac.il/tecs/ (http://www1.idc.ac.il/tecs/) It shows you how a CPU is built from the logic gates up. My only problem with it is that it's built like an exercise book, so while it explains everything in sufficient detail, it doesn't actually give you the solutions. A Google search solved that for me.
Also, the whole book is available on the site, so you cannot complain about free stuff, right?
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HI,
Nice work...
You have any idea of 8085 uP??
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Hi,
There is no logic per say programmed into processors. A processor is just a filter of sorts which takes instructions from you, closes the gates you tell it to, then processes the commands you gave it.
Utter nonsense.
If you don't recognize the illogical character of what you wrote, then at least look at the diagram you attached and get a fix on the largest (purple) block - ALU is an acronym for Arithmetic and Logic Unit. Apart from that, each tiny gate whether somewhere in a controller/processor or on its own is considered logic.
You don't even need a gate for logic, a simple inverter is logic too if you can write up a truth table for a component, it's logic.
The oldest main frame computers had logic as well, it was just relay logic, then thermionic valves, then transistors, some work with fluid, others with LASER light.
And when you program them with a line like: a = b AND (c OR d) you won't call it logic either?
Then what IS your definition of logic (apart from plain wrong :P)