The input/output unit links the microprocessor to the rest of the circuitry of the computer, passing along program instructions and data to the registers of the control unit and arithmetic/logic unit. The I/O unit matches the signal levels and timing of the microprocessor's internal solid-state circuitry to the requirements of the other components inside the computer. The internal circuits of a microprocessor, for example, are designed to be stingy with electricity so that they can operate faster and cooler. These delicate internal circuits cannot handle the higher currents needed to link to external components. Consequently, each signal leaving the microprocessor goes through a signal buffer in the I/O unit that boosts its current capacity.
The input/output unit can be as simple as a few buffers, or it may involve many complex functions. In the latest Intel microprocessors used in some of the most powerful computers, the I/O unit includes cache memory and clock-doubling or -tripling logic to match the high operating speed of the microprocessor to slower external memory.
The microprocessors used in computers have two kinds of external connections to their input/output units: those connections that indicate the address of memory locations to or from which the microprocessor will send or receive data or instructions, and those connections that convey the meaning of the data or instructions. The former is called the address bus of the microprocessor; the latter, the data bus.
The number of bits in the data bus of a microprocessor directly influences how quickly it can move information. The more bits that a chip can use at a time, the faster it is. The first microprocessors had data buses only four bits wide. Pentium chips use a 32-bit data bus, as do the related Athlon, Celeron, and Duron chips. Itanium and Opteron chips have 64-bit data buses.
The number of bits available on the address bus influences how much memory a microprocessor can address. A microprocessor with 16 address lines, for example, can directly work with 216 addresses; that's 65,536 (or 64K) different memory locations. The different microprocessors used in various computers span a range of address bus widths from 32 to 64 or more bits.
The range of bit addresses used by a microprocessor and the physical number of address lines of the chip no longer correspond. That's because people and microprocessors look at memory differently. Although people tend to think of memory in terms of bytes, each comprising eight bits, microprocessors now deal in larger chunks of data, corresponding to the number of bits in their data buses. For example, a Pentium chip chews into data 32 bits at a time, so it doesn't need to look to individual bytes. It swallows them four at a time. Chipmakers consequently omit the address lines needed to distinguish chunks of memory smaller than their data buses. This bit of frugality saves the number of connections the chip needs to make with the computer's circuitry, an issue that becomes important once you see (as you will later) that the modern microprocessor requires several hundred external connections-each prone to failure.
Winn L. Rosch Hardware Bible, Sixth Edition
Memory mapped IO is one where the processor and the IO device share the same memory location(memory) while IO mapped IO is one where the processor and the IO device have different memory located to each other.
The key for any hardware piece to work with others is the SOFTWARE. That is why anything you buy for your computer (graphics cards, hard drives, etc.) it comes with software (or the driver) to help the computer recognize it and use it for the function its meant to be used for. I hope this is what you were looking for.
Central Processor Unit --> CPU
Herz
The unit that performs the arithmetic and logical operations within the processor is called the Arithmetic Logic Unit (ALU).
It is called a micro-processor......a processor on a single chip
Because CPU is short for Central Processor Unit.
The CPU or Central Processing Unit or Processor is hardware.
"CPU" can represent "central processing unit" or "central processor unit." It is the primary computer hardware responsible for input, output, and operating on data. Note that some computers lack a CPU, as computation is spread over multiple units.
i/o unit (input/Output unit)
Micro Processor is the main processing unit of the computer. It is call Central Processing Unit. If pins are broken, it will not work.
DMA stands for Direct Memory Access, in regards to 8085 MP. It consists of 2 pins, namely, HOLD and HLDA. The former of which indicates the processor that either a peripherial or any IO device, is requesting the processor to hold its current activites and give the control of buses to IO devices. HLDA, on the contrary, is the acknowledgement from the microprocessor to the concerned IO device sending the request.