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Q: Why address bus 16 bit and data bus 8 bit?
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Size of 8086 address bus?

The 8086/8088 has an internal 20-bit address bus and 16-bit data bus. Externally, the address bus is 20-bits, and the data bus is 16-bits for the 8086 and 8-bits for the 8088.The data bus in the 8086 is 16 bits in size, while the address bus is 20.


Which processor had a 32-bit internal bus and a 16-bit external bus?

Which processor has a 32-bit Data Bus and a 24-bit Address Bus?


How multiplixed data and address bus of 8086 can be de-multiplixed?

The 8086 has a 20 bit address bus and a 16 bit data bus. The low order 16 bits of the address bus share the same 16 pins as the data bus. The low order 16 bits of the address are emitted in the first clock cycle of a memory access cycle. External logic is expected to latch that address. Then the bus becomes a data bus. The high order 4 bits of the address bus are handled separately.The determination of operand size (8 bit vs 16 bit) is made by BHE and A0. If BHE is high, it is a 16 bit operand at an even address. If BHE is low and A0 is low, it is an 8 bit operand at an even address. If BHE is low and A0 is high, it is an 8 bit operand at an odd address.


Why does microprocessor 8086 has 16 data bus and 20 address bus why aren't they equal?

The 8086 has 16 data bus lines and 20 address bus lines because that is how Intel designed it. They wanted a processor that was more powerful than the 8085, which has an 8 bit data bus and a 16 bit data bus, so they increased both bus sizes accordingly.


If the microprocessor bus has a 32-bit local address bus and a 16-bit local data bus what is the impact on the system speed?

•If the local address bus is 32 bits, the whole address can be transferred at once and decoded in memory. However, because the data bus is only 16 bits, it will require 2 cycles to fetch a 32-bit instruction or operand.


What is the difference between 8086 and 8088 microprocessor?

The difference between the 8086 and the 8088 is that the 8086 has a 16 bit data bus and that the 8088 has an 8 bit data bus. Both processors are the same 16 bit processor, and both have a 20 bit address bus. The 8086 is twice as fast as the 8088 in terms of data transfer rate on the bus for the same bus clock speed.


Consider a hypothetical 32-bit microprocessor having 32-bit instructions composed of two fields the first byte contains the opcode and the remainder the immediate operand or an operand address What?

• What is the maximum directly addressable memory capacity (in bytes)? 2(32-8) = 16,777,216 bytes = 16 MB • Discuss the impact on the system speed if the microprocessor data bus has • a 32-bit local address bus and a 16-bit local data bus. Instruction and data transfers would take three bus cycles each - one for the address and two for the data. • a 16-bit local address bus and a 16-bit local data bus. Instruction and data transfers would take four bus cycles each - two for the address and two for the data. • How many bits are needed for the program counter and the instruction register? 24 bits for the PC (24-bit addresses), 32 bits for the IR (32-bit addresses)


Size of data bus in 8086?

It is my understanding that the 80286 has a 16-bit data bus. This was a doubling of the original 8086/8088 processors.


If a memory had 16 bit address bus and a 32 bit data bus what is the largest size of the memory?

A memory with a 16 bit address bus can address 216 or 65536 distinct items. If each item is 32 bits in size, then the item is 4 bytes. The size of this memory is then 262144 bytes. (256Kb)


How does ALE signal demultiplex explain with diagram?

Demultiplexing the bus AD7-AD0 The Intel 8085 is an 8-bit microprocessor. Its data bus is 8-bit wide and hence, 8bits of data can be transmitted in parallel form or to the microprocessor. The Intel8085 requires a 16-bit wide address bus as the memory addresses are of 16 bits. The 8 most significant bits of the address are transmitted by the address bus(A8-A15). The 8 least significant bits of the address are transmitted byaddress/data bus (AD7-AD0). The address/data bus transmits data and addressinformation at different times. This is the basic need for demultiplexing the busAD7-AD0.


What is size of data bus and the address bus in 8085?

A 16-bit uP operates on instructions and data in 16-bit quantities. Therefore the databus is 16-bits. A 16-bit uP may also operate on larger quantities of data, however multiple CPU registers must be concatenated in order to maintain the data element in the uP register space. The data is always delivered to the processor 16 bits at a time. The amount of memory which it can address is a separate issue---the address bus size is totally distinct from the data bus size. The data bus determines how much memory may be delivered to the uP per cycle. The address bus size determines how much physical memory may actually be accessed by the uP. Therefore it is variable depending on how much memory is available. Typical systems today have 32-bit address busses which limit addressable memory to 4Gigabytes. (2^32) = 4G.


Is data bus the same as data width?

Not necessarily. In the 8085, for instance, this is true. In the 8088, however, the processor is a 16 bit processor with an 8 bit data bus. The same is true for the 80386sx - it is a 32 bit processor on a 16 bit bus.