Interfacing 8255 to 8086 in I/O Mapped I/O Mode:

 The parallel communication interfaces with the microprocessor. Interfacing 8255 to 8086 in I/O Mapped I/O Mode:

· 8086 has four special instruction in I/O Mapped I/O Mode: IN, INS, OUT,OUTS

· Only 256 address can be generated

· Only lower data bus is used as 8255 is 8-bit device

· Direct addressing mode is used.

Interfacing 8255 to 8086 in Memory Mapped I/O:

· 20 address lines to identify an I/O device

· I/O device is connected to memory register

· Address lines are used by 8255 for internal decoding

· Same control signals are used to access I/O as those of memory.


Comments

Post a Comment

Popular posts from this blog

Artificial Intelligence

Image
Artificial Intelligence 1.    What is AI technique? Artificial  Intelligence (AI)  is  the study  of  how  to make computers do things which, at  the moment, people do better. It is a method that exploits knowledge that should be represented in such a way that: ·    The knowledge captures generalizations. ·    It can be understood by people who must provide it. ·    It can be easily modified to correct errors and to reflect changes. ·    It can be used in situations even if it is not accurate and complete. ·    It helps to narrow the range of possibilities that is has to be considered. 2.    What are the steps to be considered to solve a problem? To solve a particular problem, the following steps are taken into account, ·    Define the problem precisely. ·    Analyze the problem. ·    Isolate and represent the task knowledge that is necessary to solve a problem. ·    Choose the best problem-solving techniques and apply it to a particular problem.
Read more

The taxonomy of CASE Tools

CASE Tool Taxonomy CASE tools can be classified by · by function, · by user type (e.g. manager, tester), or · by stage in SE process (e.g. requirements, test) The following taxonomy is classified by function. Business Information Tools model business information flow. The tools represent business data object and model their flow. Network tools could be modified to yield the same functionality. Process Management Tools model processes. You have to understand the process in order to model it. The tools help you capture process. This is a key component of TQI. Project Planning Tools help plan and schedule projects. Examples are PERT and CPM. Finding parallelismand eliminating bottlenecks assist in streamlining projects. Risk Analysis Tools helps build a risk table from the schedule outlining the risk each component of the production process and categorizing the risks as catastrophic, critical, marginal, or negligible. A cost is associated with eac
Read more

Zoho Second round - adding a digit to all the digits of a number

Adding a digit to all the digits of a number eg digit=4, number = 2875, o/p= 612119 C Program: #include<stdio.h> #include<conio.h> #include<string.h> int main() {     int t,n,i=0;     char num[100];     printf("Enter the digit: ");     scanf("%d",&n);     printf("Enter the number: ");     scanf("%s",num);     printf("o/p ");     for(i=0;i<strlen(num);i++)     {     printf("%d",num[i]-'0'+n);     }  getch();  return 0; }  
Read more