TIMER1

The PC dedicates TIMER1 to generating DMA requests for dynamic RAM refresh. This is not needed in a Hornet system. In the Hornet system TIMER1 is a general purpose timer. It's output is ORed with other sources to cause an IRQ2 interrupt. It is intended to be used for generating keyscan interrupts (see the chapter entitled KEYBOARD).

    SIGNAL  CONNECTION
    ================================
    CLK1    1.193182MHz (nominal)
    GATE1   VDD (always enabled)
    OUT1    causes IRQ2 interrupt