​​Data percorendo the bus.

​​Data percorendo the bus.

1 - The signal processor or other components undergo several parallel lines of the circuit. The number of lines
depends on the type of architecture used by the bus. The simplest - the 8-bit bus used in the original IBM PC
- Uses sixty-two lines to connect expansion boards. Any signal sent to a board is received by
all others.

2 - Eight lines to transmit electricity boards. Different lines have different voltages.

3 - Eight of the thirty-two lines are used to transmit any data, whether the data is intended
the memory chips, the monitor or the disk controller.

4 - Twenty lines carry information that determines the address where the data should be taken. Each expansion card
uses a unique address and specific - all available from the first megabyte of memory - that can be addressed
by the operating system.

5 - The remaining lines are used to transmit control signals to certain specific commands such as
read and write commands to the memory device and for each input / output.

6 - Each board bus constantly looking for signs in the appropriate command lines. When a sign appears
the command line recording, for example, all input / output acknowledge the command, and circuitry
Memory not.

7 - The boards I / O alerted by the write command, the lines are aware dc address. If the specified address
these lines is not used by the card, it will ignore the signals sent by the data lines.

8 - If the signals from the address lines match with the address used by the card, accepts this data sent
by lines, using them to supplement the recording program.

Note - Recently, a new form of communication with peripherals gained popularity. This is the place bus or
local bus, which overcomes the speed limitation imposed by the other bus designs. Original bus 0
was designed to operate at 8 MHz, about twice as fast as the processor of the IBM 8088 PC. While
Processor speed increased to 10 MHz, 25 MHz, 33 MHz, 50 MHz or more, the bus remained at 8 MHz with the
Local bus design, it has become possible to transmit 32 bits of data in the local speed of the processor of the PC.
Generally, a PC with local bus architecture limits this to one or two slots, used by video cards or
disk controllers, where speed is necessary. The slower expansion slots are used for communication
with the serial and parallel ports and the keyboard, where speed is not as important a factor.

Source: Evolution of Computers