Hi Rovan

You can try a resistor (e.g. 1kOhm) from the port pin
to VCC to get a stronger high level.

Also not all triacs accept negative gate voltage (see data sheet).
So I suggest using a transistor to invert the level
and connect MT1 to GND.


Also watch the crazy P1 of the 2051, if P3.4 was
low during reset. Look at:
http://www.specs.de/~danni/errat/e89c2051.htm


Peter