|A bus is a collection
Diagram A is
a four bit bus.
Zeros and ones
can be put on the bus, 0 volts for zero and +5 volts to represent a one.
number that can be put on a four bit bus is 0000.
is 1111 which is 15 in decimal and F in hex.
different numbers can be placed on this bus, 0000 being the lowest and
1111 the highest.
Rather than draw
four wires,we use the representation shown in diagram B.
systems use a eight bit data bus.
number that can be placed on it is 00000000.
number is 11111111 which is equivalent to 255 in decimal.
different numbers can be placed on this bus.
255 in decimal
is FF in hex.
A sixteen bit
bus is shown in diagram C.
number we can put on this bus is 0000000000000000.
number is 1111111111111111 which is 65535 in decimal.
different numbers can be put on this bus.
65535 in decimal
is FFFF in hex.
All the registers
in the memory chips have their own individual addresses, like house numbers
in a street.
By putting its
address, in binary, on an address bus we can select any individual register.
are commonly 16 bits, so we can select any one of 65536 registers.