hi, i'm having problems using timers in AT89C51. I have a timer in an interrupt handler routine. As soon as the "output" variable gets a rising edge, the program enters in the interrupt handler routine. Now the problems start. I have to run the timer for as long as the "output" variable is high. (16 bit mode) This sounds simple enuff but fer some reason i cant do it.(the timer just doesnt run....I have used thew following settings ... TR0 = 1...TMOD = 0x01.... It would be a great help if someone can assist me with the code for this issue. Thanks