Posts Tagged ‘cpu’

Segementing how a microprocessor manages more than 64K of memory

April 25, 2013

Segmenting is a memory management technique which microprocessors use to address more than 64kilobytes memory.In this example I will demonstrate how
Intel 8086 accomplishes addressing more than 65K memory.

A memory word is addressed by addressing by  adding a segment pointer and a word address as shown
in the picture.

The possibility of addressing one megabyte doesn’t necessary mean that the processor has a physical memory of 1MB.
You can make a program as if the processor had 1MB of memory and the
processor can fetch the segment that is being addressed from the computers hard drive.

moreThan64KAdressing

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Writen by: Rikard Grossman-Nielsen
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How microprocessor perform I/O mangament:polling, direct memory acess and interrupts

May 9, 2012

This post will be abou the first method called polling. The next two posts will cover the other methods.
The first method is called polling. Polling is also called programmed I/O, and it’s also the simplest one to implement from a hardware perspective. I/O units are connected to the system data and an address buss in a  regular fashion trough necessary circuitry. Depending on the type of microprocessor they can also be connected to certain lines on the control buss.

The goal with a communication schedule is to have a well ordered procedure to decide what I/O unit is to be served by the processor next. Polling is a synchronous method since it doesn’t interrupt the program which is currently executed by the microprocessor. When polling is used the microprocessor will on regular intervals ask each unit connected to the data buss if it needs to be served.  The sensing if a unit needs to be served is in practice done by sensing a flag bit in the status registry of the unit.

The advantages of polling are:
1. It requires very little hardware and no dedicated lines.
2. it’s synchronous with the execution of the prgoram. This is a big advantage since the programmer know s exctly when an external unit is polled and who long time it takes to serve that unit.

The disadvantages of polling are:
1. It requires special hardware if interrupt management is to be done outside the microprocessor.
2. Each time an interrupt is made, there’s an overhead time to manage the interrupt

Description of polling techonology

Description of polling techonology

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Writen by: Rikard Grossman-Nielsen
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Comparing netbook chipsets AMD C50 and AMD C60

February 15, 2012

My netbook Acer Aspire One 522 has an AMD C60 chipset. There’s also a sibling to this chipset called AMD C50. The difference between these two chipsets are that the AMD C60 has a turbo function for the processor and the GPU which means that it can speed up when there’s a need for extra speed. The downside is that this turbo function makes the components hotter so you can only use the turbo for a limited amount of time. otherwise the chips will overheat. You can also check out this link for a more detailed comparison of the two chipset.

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