How can I control Phase angle of Triac using 8051 ?

[baileychic]

How can I control Phase angle of Triac using 8051 ?

I have successfully controlled Triac Phase angle using PIC microcontrollers but how to control phase angle of triac using 8051 series microcontrollers ?

My mains voltage is 220V 50 Hz AC.

Find the attached circuit. The ZCD is a square wave and I can detect only falling edge with 8051. So, I can only control only half cycle of AC.

Edit:

Sorry, the circuit was wrong. Here is the new circuit. Previous circuit removed.

 

[betwixt]

The principle is the same whatever MCU you use. Why do you say you can only detect falling edges with an 8051, they are perfectly capable of polling a logic input to find either edge.

Brian.

 

[baileychic]

Thanks for the reply. I was able to get the code work fine.