[AVR] Can someone share a simple code snippet for blinking an LED using the AT89S52 microcontroller? How can I modify the code to change the blinking freq.

[Rash23]

• Can someone share a simple code snippet for blinking an LED using the AT89S52 microcontroller? How can I modify the code to change the blinking frequency of the LED? reffered tutorial from Programming AT89S52 Microcontroller to Blink LED

 

[KlausST]

Hi,

AT89S52 is no AVR .. its an 80C52 compatible microcontroller.

Many thousands of examples/tutorials/explanations/videos in the internet. I guess it´s one of the most often posted examples.
I personally don´t think we need another one.

Klaus

 

[D.A.(Tony)Stewart]

Hi,

AT89S52 is no AVR .. its an 80C52 compatible microcontroller.

Many thousands of examples/tutorials/explanations/videos in the internet. I guess it´s one of the most often posted examples.
I personally don´t think we need another one.

Klaus

Klause maybe you can use your compiler to convert from your fave AVR tool into 80C52 machine code. But I didn't see AVR in the question.

--- Updated Jan 16, 2024 ---

I wonder who came up with the cute "Blinky" name for their code

#include <REGX52.h>
delay(unsigned int y){
unsigned int i,j;
for(i=0;i< y;i++){
for(j=0;j< 1275;j++){}
}
}

main(){
while(1){
delay(1000);
P1_0 = 0;
delay(1000);
P1_0 = 1;
}
}

 

[KlausST]

Klause maybe you can use your compiler to convert from your fave AVR tool into 80C52 machine code. But I didn't see AVR in the question.

* Compiler: I don´t have an 80C52 / 89S52 compiler.
* AVR: I did read it in the headline.


Klaus

 

[D.A.(Tony)Stewart]

* Compiler: I don´t have an 80C52 / 89S52 compiler.
* AVR: I did read it in the headline.


Klaus

Ja, the case of a missing correct tag.

 

[Aussie Susan]

That type of 'delay' function (post #3) is very error prone for a coupel of reasons:
Firstly it depends totally on the clock frequency for the timing using it's 'magic number'. That is when it works at all!
Secondly, many compilers, even with the lowest level of optimisation, will see the two loops as 'empty' and remove them. Therefore the function will simply return immediately.
How you make a proper delay function really depends on the environment. Sometimes making the loop variables 'volatile' works, but as they are local the compiler might still not generate any code.
You can use assembler which generally means the code will not be optimised. Many compilers will provide a delay function in their runtime library that is either a tested externa function or a macro that generates in-line assembler.
You can also use a timer.
Susan

 

[betwixt]

Unless the compiler assumes functions don't return values, the delay(){...} should also be declared "void". I would expect a warning from the compiler without it.

Brian.