This driver is actually a combined driver for the Clock and the High Resolution Timer. This driver must be combined since both times are implemented using the same hardware: the 8253 timer chip, channel 0.

This driver calls RTKIRQTopPriority(1,8) at initialization to ensure that the timer interrupt is processed with the lowest interrupt priority. Applications requiring a different interrupt priority distribution should call RTKIRQTopPriority again after RTKernelInit.

This driver cannot be used in APIC mode.

Requirements: 8253 timer chip at address 40h, interrupt controller 8059A at address 20h, timer generates IRQ 0. Incompatible with drivers CLKPC and HRTPC.

Left Kernel Clock

Driver CLKPC

Down Driver CLKRTC