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Often Things are Really Simple When You Get Down to the Basics by Britt Storkson Owner, P2FlowLLC I work with microprocessors - a big, fancy-sounding term - but when you look at what it basically does, it’s simple. All a microprocessor does is “sense” electrical voltage levels. That’s all. It can “sense” whether a voltage level is near the high voltage powering the device (called logic “1”) or near the low voltage powering the device (called logic “0”). No big deal, right? These voltage levels can be trans- ferred from the “pin” (external “lead” on the device which is used to connect it to the printed circuit board) on the micro- processor into (input to) the microproces- sor to be stored, or output to another “pin” on the microprocessor. What’s so great about being able to “sense” and store electrical voltage levels? Storing voltage levels is called “mem- ory”. One voltage level containing a logic “1” or logic “0” is called one “bit”. This “bit” remembers the state you put it in forever, until you change it. There are some conditions to this memory storage which I won’t get into for clarity, but that’s basically how it works. By combining 8 “bits” we get a “byte”, which is how most memory is measured. This combination of bits into a byte gives us a binary (bi meaning two, and nary meaning numerical) value of 256. These are powers of 2. 1 bit = 2 possible states, 2 bits = 4 possible states, 3 bits = 8 possible states, and so on until we get to 8 bits which provides up to 256 possible states. It’s actually 255 total because zero is included. Now we have created a number or, more correctly, a value. On this value we can perform basic arithmetic (addition, subtraction, multiplication, or division) on these values or compare one value with another to see if one is greater than, less than, or equal to one another. We can also set (make a logic 1), clear (make a logic 0) to alter its operation, or test (check to see if it’s a logic 1 or 0) any bit within the byte to make decisions. Each byte location is numbered so we can find it within the memory. This location number is called an “address”... just like a home address...where it “lives”. With computer memory, not only do we need to know what is in the memory (called the data), but where it lives (called the address). Where the data is gives it meaning. If I put my age (59) in address location #100, I know the address represents my current age. Instructions (also binary values) stored in a separate memory direct what the microprocessor does. A “clock”... simply a voltage that transitions from a logic 0 to a logic 1 like a turn signal flasher but much faster...that “clocks” at a stable frequency which “steps” through (executes) the instructions in the proper order to make the micro- processor deal with the tasks at hand. Microprocessors are very fast. Ex- ecution speeds of 1 million instructions per second are not uncommon anymore. Each instruction is a very simple task, but the task can be done very quickly so much can be accomplished in 1 second. Microprocessors are also very cheap with complete, very capable micro- processors costing less than 50 cents each in production quantities. The reason microprocessors are used in just about everything anymore is because they are cheap, reliable, and require very little power in most appli- cations. Often, they can prevent dam- age or alert the equipment operator to possible problems. Adding microproces- sor control to a piece of equipment is now the rule, not the exception. Britt admin@ worldwidedrillingresource.com 65 WorldWide Drilling Resource ® JULY 2014 4< /*2'3* "& > > > > ,'< ? /2+ '6* /3+6 /3+6 ')1/3- " " !8=2+ /7843 4* 4* ')1/3- !+8 5)7 !8'3*'6* $'2:+ 9((+6 6':+2 $'2:+ 9((+6 !+'87 9((+6 $'2:+ 37+687 #6+8.'3+ $'2:+ 37+687 $'2:+ !56/3- ! ! $'2:+ 4:+6 '71+8 ? !;/:+2 ')1/3- ? !+6/+7 ? !+6/+7 ? !+6/+7 ? !+6/+7 ? !+6/+7 ? !+6/+7 < /3+6 < /3+6 < /3+6 < /3+6 < /3+6 6/)+7 !9(0+)8 "4 .'3-+ %/8.498 48/)+ !@ @ < < < < <