Concepts of an address and data, Computer Engineering

Assignment Help:

The heart of a computer is often one integrated circuit; one typical circuit is a 68Hc11 Microprocessor. Let us consider a typical 68Hc11 hardware design.

2125_Concepts of an address and data.png

          The microprocessor has three parallel connection of wires (buses).Attached to these buses are memory storage devices (RAM, EPROM) and input/output connections (serial /parallel).The microprocessor can communicate to any of these devices by means of the buses . The device can be selected by sending down a unique address number on the address bus and the information to be send or received is transferred via the data bus. It is often liken to that of a telephone call, the phone number is the address of the device and the conversation is the data .Within a system ,  it is common to have a description of the allocation of these address' in the form of a memory map.

This is simply a plot of address against data and indicates what address' are used be what devices. A typical memory map for a system is shown. Here the system uses two I.C's namely EPROM (non volatile storage), Ram (volatile storage), with internal parallel and serial port. Let us look at the operation of the microprocessor in a little more detail. The program is assembled from Assembly language into binary and stored in EPROMS, as shown below:

Assembly language program
name ex1  ;Immediate data example
p6811    ;set processor type
org $500  ;Start on external ram
ldaa #$fe  ;load Acc A with fe hex
adda #$1  ;ADD 1 TO a
end
 
Address  Assembly Code
000500    86
000501    FE
000502    8B
000503    01
00FFFE    05
00FFFF    00

 On power on the microprocessor issues a reset which causes the processor to go into a vector mode, this in turn reads in the next two bytes starting at address FFFE. The data stored at this location represents the initial program counter (PC) the data is then loaded PC respectively i.e. PC = 0x0500. This causes the processor to read the data at the address 0x500. The microprocessor reads in 0x86 and understands that the first piece of data must be a program command. It interprets 0x86 as a LDAA # data instruction and the data must follow .Therefore the microprocessor increments the PC to 0x501 and reads in the immediate data 0xfe. This is known as the 'FETCH' cycle because the microprocessor has fetched the instruction. The next stage is the 'EXECUTION 'cycle. Here the microprocessor transfers the data 0xfe into accumulator A and increments the PC to 0x502 and fetches the next instruction. A day in the life of the microprocessor is simply one of fetching and executing. Within C we often want to access the memory map directly, in order to talk to I/O devices or alter data in RAM . For this purpose C allows us to use the concept of address pointers.


Related Discussions:- Concepts of an address and data

Recurrence relation, Take the following recurrence relation consider only f...

Take the following recurrence relation consider only for n = 2k for integers k ≥ 1: T(2) = 9, and for n ≥ 4, T(n) = n + T(n /2). Three students were working together in a stu

What do you mean by resolution, Q. What do you mean by Resolution? Reso...

Q. What do you mean by Resolution? Resolution is parameter which defines possible sharpness or clarity of a video image.  Resolution is defined as number of pixels which make u

Explain working of intranet, Intranets are mainly "small" Internets. They u...

Intranets are mainly "small" Internets. They use same network facilities that Internet does, though access is restricted to a limited sphere. For example, a company can set up an i

Explain the multiple bus organization structure, Explain the multiple bus o...

Explain the multiple bus organization structure with neat diagram. The multiple bus organization is using more buses instead of one bus to decrease the number of steps needed an

Explain register marker, Explain Register marker. Register marker: St...

Explain Register marker. Register marker: Strowger selectors doing searching and counting. Conversely, the crossbar switch has no 'intelligence'. Something external to the

What are the different layers in r/3 system, What are the different layers ...

What are the different layers in R/3 system? There are three layer:- Presentation Layer. Application Layer. Database Layer.

Earned value analysis, Senior management has requested a status update on t...

Senior management has requested a status update on the workstation installation project.  As a part of this update, managers have requested that you present an Earned Value analysi

Is it possible to decrease clock skew to zero, Is it possible to decrease c...

Is it possible to decrease clock skew to zero? Describe your answer? Even if there are clock layout strategies (H-tree) which can into theory reduce clock skew to zero by havi

Poor human support - obstacle to information system, Poor human support - O...

Poor human support - Obstacle to Information System The full utility of an IS will only be realised if it is properly supported by the users. Technology is never a solution in

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd