This driver uses the MC146818A CMOS Real-Time clock hardware to generate timer interrupts. It only supports frequencies which are powers of two in the range 2 to 8192. Timer intervals set with CLKSetTimerIntVal are rounded to the nearest supported interval. At program startup, the timer interrupt frequency defaults to 1024 or 0.9765625 milliseconds.

This driver calls RTKIRQTopPriority(3,9) 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.

Requirements: MC146818A CMOS Real-Time clock chip at address 70h, interrupt controller 8059A at address 20h, timer generates IRQ 8, RTTarget-32 4.0.

Left Kernel Clock

Driver CLKHRTPC

Down Driver CLKAPIC