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A memory mapped IO device is an IO device that responds to a specific address when IO/M- is low. A peripheral (or IO) mapped IO device is an IO device that responds to a specific address when IO/M- is high.
Many system designers ignore IO/M- in favor of memory mapped IO.
- This eliminates one term in the chip select logic for every device.
- This allows you to use all addressing modes and instructions when manipulating an IO device, as opposed to using only IN and OUT.
- This allows you to potentially have more than 256 different IO devices.
The downside is that you reduce the addressable main memory in the system, i.e. you cannot have all 64K available to you, but this is not generally a problem in most controller designs. You also must decode 16 address lines instead of just 8 when accessing the device.
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Differences between physical addressing and logical addressing?
In computer architectures, a logical address is the address at which a memory location appears to reside from the perspective of an executing application program. This may be different from the physical address due to the operation of a memory management unit (MMU) between the CPU and the memory bus. Physical memory may be mapped to different logical addresses for various purposes. For example, the same physical memory may appear at two logical addresses and if accessed by the program at one address, data will pass through the processor cache whereas if it is accessed at the other address, it will bypass the cache.
Difference between dynamic and static memory?
dynamic is the study of motin,while static is at rest it means that the memory which is used at motin time as by usic calloc,mallaoc,free function ,on the other hand static is the memory which only used at compile time or at the time of work in during progrmming,static memory has drawback ,the drawback is that in this memory ware unable to use the excess memory as we allocate already to cover or improvre this type of problem we use dynamic memory allocation.
What is basic difference between shortcuts and icons?
Shortcuts and icons have a few basic differences between the two. A shortcut can be deleted from one place and still stay in another space. An icon might only be in one area, unlike a shortcut. A shortcut uses use less memory, an icon uses much more memory.
Difference between variable and constants in visual basic?
"Memory locations that hold data that can be changed during project execution are called variables; locations that hold data that cannot change during execution are called constants"
What is difference between demand paging n pure demand paging?
In demand paging, a page is not loaded into main memory until it is needed. In pure demand paging, even a single page is not loaded into memory initially. Hence pure demand paging causes a page fault. Page fault, the situation in which the page is not available whenever a processor needs to execute it.
Differentiate between memory mapped IO and IO mapped IO?
Memory mapped IO is one where the processor and the IO device share the same memory location(memory) while IO mapped IO is one where the processor and the IO device have different memory located to each other.
What is the Difference between memory mapped IO and IO mapped IO in 8085 mp?
In the 8085 microprocessor, memory-mapped I/O uses the same address space for both memory and I/O devices, allowing up to 64 KB of I/O addresses. In contrast, I/O mapped I/O (also known as port-mapped I/O) utilizes a separate address space for I/O operations, which allows for a limited number of I/O devices to be addressed (up to 256 8-bit ports). The instructions for accessing memory-mapped I/O involve standard memory instructions (like MOV), whereas I/O mapped I/O requires specific instructions like IN and OUT. This distinction affects how devices are interfaced and programmed.
What is the Difference between memory mapped IO and IO mapped IO?
In memory mapped I/O, a chunk of the CPU's address space is reserved for accessing I/O devices. In I/O mapped I/O, I/O devices are handled distinctly by the CPU and hence occupy a separate chunk of addresses predetermined by the CPU for I/O. In case of Memory mapped I/O the same address BUS is used for accessing both Memory (RAM) and the Registers of I/O devices. For I/O Mapped I/O, separate address BUS is used. As Address space is generally larger for Memory than I/O registers, the length of I/O address is larger in case of Memory Mapped I/O. For a system which uses I/O Mapped I/O, there is a requirement for a extra h/w Circuitry.
What is a memory mapped register?
A memory mapped register is a register that has its specific address stored in a known memory location.
How are peripheral devices logged to the CPU?
Peripheral devices are connected and logged to the CPU through interfaces like USB, SATA, or PCIe, which facilitate communication between the device and the processor. When a peripheral is connected, the operating system detects it using device drivers that manage data transfer and functionality. The CPU then communicates with the device through memory-mapped I/O or direct I/O, allowing the system to recognize and interact with the peripheral efficiently.
What is a portion of memory that is allocated to a device?
A portion of memory allocated to a device is commonly referred to as a memory-mapped I/O space or device memory. This area of memory is reserved for the device to store data related to its operations, such as buffers for input/output processing. It allows the CPU to communicate with the device by reading from and writing to specific memory addresses associated with that device. This allocation is essential for efficient data transfer and control between the CPU and peripheral devices.
What is the difference between a regular memory card and an Ultra Memory card.?
What is the difference between a regular memory card and an Ultra Memory card
Difference between multistore and working model memory?
what is the difference between the memory store model and the working memory model?
What is the meaning of memory mapped bus?
Memory mapped buses helps in the extension of the address of the physical ram through which the devices can access the address
Is memory card reader a peripheral and non peripheral?
peripheral device
Where you connect the peripheral devices in 8085?
In the 8085 microprocessor, peripheral devices are connected through the Input/Output (I/O) ports. The microprocessor has a total of 16 address lines, allowing it to address up to 256 I/O ports (from 00H to FFH). Peripheral devices can be interfaced using either memory-mapped I/O or I/O-mapped I/O, depending on the specific design of the system. Typically, the connection is established through interfacing circuits like decoders, which help in selecting the appropriate device for communication.
What the difference among direct mapping associative mapping and autoassociative mapping?
Direct mappingA given Main Memory block can be mapped to one and only one Cache Memory line.It is Simple, Inexpensive, fastIt lacks mapping flexibilityAssociative mappingA block in the Main Memory can be mapped to any line in the Cache Memory available (not already occupied)It is slow, expensiveIt has mapping flexibility
