[SOLVED] how to detect rising edge on 8051

[ud23]

hi all i want to detect proxy output any pin of 8051 but i want to detect on rising edge only. i know with external interrupts its possible only falling edge

 

[ibrar]

Do you need interrupt or not?
IF not then i think it is very simple.
when your pin goes from "0" to "1" it is your rising edge.

regards

 

[ud23]

no i don't need interrupts. as you said it is rising edge but how to detect in c i know "0" to "1" also consider as state change for that pin i need to take action only while perticular pin goes from"0" to towards "1" not when its become after complete "1".

 

[ibrar]

What i understand that u want to take action in time between a particulate pin start changing its state from "0" to "1".
If yes then i think that is not possible using a digital input. You can use an analog input for this purpose. When ADC goes from low value to high value you can take action.

Regards

 

[aameer]

you make that pin in a while loop.. i mean
for eg,

sbit input=P2^0;
main()
{
   while(input==0);//wait till rising edge
    
  // next action

}

 

[arun_9998]

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Code C - [expand]
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sbit input=P2^0;
bit flag;
main()
if(!input)
flag=1;
if(flag&&input)
{//this is for rising edge 
//do action on rising edge
flag=0;
}

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---------- Post added at 10:55 ---------- Previous post was at 10:27 ----------

hi all i want to detect proxy output any pin of 8051 but i want to detect on rising edge only. i know with external interrupts its possible only falling edge

try this

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Code C - [expand]
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#include<reg51.h>
sbit in=P2^0; //input for rising edge
sbit led=P2^1;//led toggle on rising edge
bit flag; //for lavel chang on input pin 
void main()
{
led=0;
in=1;//for input
while(1)
{
if(!in)
flag=1; //flage set on input pin is low
if(flag&&in)//for pin state change low to high
{
led^=1;
flag=0;//flag reset while pin is high
}
}
}

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