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The data bus in the 8086 is 16 bits in size, while the address bus is 20 (16bits would only address 64KB of memory, an extra 4 bits allows to address the total of 1MB, this is done trough segmentation of the memory).
To form a multiplexed of data bus and address bus, four bits of 8086 address bus are grounded.
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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.
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 much memory can be address with 32 bit address bus?
32 bit address bus can access more than 4 gigabytes (232) of memory. Sandeep Kr. Singh (MCA)
What does the size of the address bus affect?
The size of the address bus affects the maximum amount of memory a computer can directly access. Specifically, it determines the number of unique memory addresses that can be generated, which is calculated as 2 raised to the power of the address bus size (in bits). For example, a 32-bit address bus can address up to 4 GB of memory, while a 64-bit address bus can theoretically access 16 exabytes. Thus, a larger address bus allows for greater memory capacity and can enhance overall system performance.
How many bytes of date can be addressed by a computer system with an 11-bit address bus and an 8-bit data bus?
There can be one byte of data transferred at one time on the 8-bit data bus, but without knowing more about the architecture and the address and data bus multiplexing we cannot know how many bytes can be addressed.Perhaps the machine architecture uses 2 address bus cycles to send out a 16-bit address and 6-bits of control signals, then uses 2 data bus cycles to read or write the 16-bit word at that address, which would mean this computer system addressed two bytes at one time.Perhaps the machine architecture uses 3 address bus cycles to send out a 32-bit address and a 1-bit control signal, then uses 4 data bus cycles to read or write the 32-bit word at that address, which would mean this computer system addressed four bytes at one time.Perhaps the machine architecture uses 6 address bus cycles to send out a 64-bit address and 2-bits of control signals, then uses 8 data bus cycles to read or write the 64-bit word at that address, which would mean this computer system addressed eight bytes at one time.Perhaps the machine architecture has a variable word length (which could be specified in many different ways depending on the architecture), in which case almost any number of bytes could be addressed at one time (with different numbers of bytes in each addressing operation).There are many other possibilities.
What should be the minimum size of address bus?
The minimum size of an address bus depends on the amount of memory the system needs to access. To calculate the minimum size, you can use the formula (2^n), where (n) is the number of bits in the address bus and determines the number of unique addresses it can generate. For example, a 32-bit address bus can address (2^{32}) locations, or 4 GB of memory. Therefore, the minimum size of the address bus must be large enough to accommodate the maximum memory requirement of the system.
What is a property of an Address Bus?
An address bus is a vital component in a computer's architecture that carries addresses from the CPU to other components, such as memory and input/output devices. Its width, measured in bits, determines the maximum addressable memory capacity; for instance, a 32-bit address bus can address up to 4 GB of RAM. Additionally, the address bus is unidirectional, meaning it only transmits data from the CPU to other devices, not the other way around.
Was atari 2600 4 bit?
No, there were no 4-bit consoles. The 2600 uses the 8-bit 6507 CPU and an 8-bit bus.
What is the purpose of an address bus?
The address bus is used by the processor in a computer to locate a piece of data from the RAM (Random Access Memory) that it needs to access. No real data is carried via the address bus, as this is the job of the Data Bus. The pieces of data that the address bus locates are called "addresses" and the address bus transfers "data addresses" to and from the control unit.
How many times can a 32 bit bus can handle versus the data bits as an 8 bit bus?
Assuming the raw bus speed is the same, you should be able to move 4 times as much data across a 32-bit bus as across an 8-bit bus, because there are 4 times as many bits. It's never that simple, though. The 8-bit bus on the original IBM PC was a 1.3MHz bus, and so could move about 1,300,000 bytes per second, flat out. The 32-bit bus specified by the VESA consortium for the 486 was a 33MHz bus and so could move 133,000,000 bytes per second, flat out. The multiplier in this case as closer to 100x.
What is meant by multiplexed address data bus?
Multiplexing of the data and address buses is done to reduce the pin count on the microprocessor chip. The address information is emitted at the beginning of a memory cycle, and external logic is expected to latch that address. Then the bus becomes the data bus and the required data is transferred to or from memory using the latched address.In the 8085, this saves 8 pins at the cost of 1 pin, ALE. In the 8086/8088, this saves 16 pins at the cost of 1 pin, ALE. In some architectures or modes, there is no ALE, but the external logic is still required to know when to latch the address based on some other criteria.As an example of that, in the original Intel 4004, the microprocessor's bus was 4 bits, while the address bus was 12 bits. There were 8 clock cycles. In the first three, external logic was expected to latch the three 4 bit parts of the 12 bit address. Similarly, in the next two, the resultant opcode, which as 8 bits, was multiplexed by the external logic into two 4 bit parts. (The 4004 was only a 16 pin chip, but it packed a lot of complexity in its day, being the world's first microprocessor.)
What is the typical bus width of an Intel Pentium 4?
32 bit is the default.
