In Microprocessor based system devices are connected n parallel through the bus in this situation it is required that one device is interact with the bus at a time .If more than one device make communication wid bus then more then one signal is places that they will produce damaging current known as Bus Contention.To avoid bus contention tristate buffer are placed between buses and peripheral...
Tristate devices are used in bus based systems to allow multiple bus drivers to control the bus, each at different times, while all the rest are allowed to read the bus. Only one device can drive the bus at any one time. All the others "tristate" or float, so they neither drive the bus low nor high.
the bus through which the data are transmitted or received within microprocessor and with peripherals is called as data bus.when used internally to microprocessor called internal data bus.
Two ground pins are used in the 8086 microprocessor to increase the bus pull-down current capacity.
The most common application of tri-state logic is in the use of LED circuits. They can also be used on a shared electric bus.
Latches in Microprocessor are used for demultiplexing address/data bus.
A tristate device is a device that has three states instead of two. The normal states are low and high, where the output is pulled down or up by turning on one of the two output transistors. The third state is floating, where neither transistor is turned on. Tristate devices are useful in a bus design where, for instance, more than one device can drive a data bus, but only one at a time.
The address bus is a section of the bus that emits the address of the desired instruction or operand.
ad is multiplex address data line bus
A bus consists of wires which is used to transfer data either in serial or parallel transmission.
since data can be read /write from/to the microprocessor, hence data bus is bidirectional. if data is required read from microprocessor then it will be pointing to a memory location by the address bus, by indicating which location data its required to read. similarly to write a data to a location, again the microprocessor will be to that particular location by holding that address in address bus. hence it will be unidirectional.
Data enable, signals that bus lines are being used to transfer data
Bus cycle is a single transaction between the main memory and the CPU.