Now lets come to instruction sets of micro controller. The instruction set can be classified as shown below. Note:- micro controller belongs to the MCS family of micro controllers. This basically means,any variant micro controller that comes under the MCS family made by any other manufacturer must use the same set of instructions made for MCS
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Resistor 1k t0 4. We are going to blink an led connected to pin 1 of 89c51 microcontroller. Pin 1 corresponds to microcontroller Port-1 pin 0.
The pin is initialized as output pin in the code. Crystal is connected to microcontroller in parallel to two pf capacitors. Ground pin Now we are done all the necessary connections are made. Circuit Diagram of blinking led with 89c51 microcontroller is given at the right side. Led polarity is anode facing the power supply and cathode is connected to port 1 pin 0.
Blinking Led with 89c51,89c52 Led is connected to port-1 pin 1. Resistor is used to limit the amount of current led is consuming. So when the microcontroller sources some voltage the led turns off and when it grounds the led turns on.
Opposite polarity functionally by microcontroller pin. In the code above I first included the header file reg When ever we are using 89c51 microcontroller in our project we have to include it. If we are using 89c52 than the file name changes to reg This library contains default function definitions and configuration for series microcontrollers.
Note: I am using keil software to write my code to blink an led. If you are using any other software to write code for microcontroller. Then first check which library that software made compulsory to be included for writing code of series microcontrollers. Actually the compiler that is working with keil needs this header file to compile the code and generate Hex code for you. Now we can use Port-1 Pin 0 with the name of Led. You can see the two for loops in the delay function.
These two for loops are providing us random delay. The first loop runs number of times for the value which is given to it, and second loop runs 5 times for each iteration of the first loop. We usually pass some big number as parameter to the function and this huge number makes the for loop runs for some seconds to minutes depending on our given integer value.
It is necessary to initialize each port as input our output before using it in the program. Since Port-1 of microcontroller consists of 8-Pins. If 0 is written on Pin it initializes the pin as output. If 1 is written it initializes the pin as input. Initializing Port-1 of 89c51,89c52 microcontroller. While 1 Loop is continuously running the logic present in it.
The whole cycle is below. Then Some Delay Keeps Led in on state. Then Some Delay keeps led in switch off state. After the above cycle is completed while loop starts again and this makes the led to seem like blinking.
Download the Project files, Code Hex,C. Simulation is also present in the folder. Code is written using C language. Keil software is used to write and compile code. Simulation is made in Proteaus 8. Watch the project video Here…….
How to blink an led using 8051(89c51,89c52) series Microcontrollers
8051 Programming Tutorial-Chapter 1