ADLINK Technology cPCI-3920 Series User Manual

Contents

ADLINK Technology cPCI-3920 Series User Manual Manual pdf 38 page image

28 Functional Description3.2 PeripheralsThe following standard peripherals are available on the cPCI-3920board:TimerThe cPCI-3920 is equipped with the following timers:Real-Time ClockThe IICH contains real-time clock with 256-byte of battery-backed RAM.The real-time clock performs timekeeping functions andincludes 256 bytes of general purpose battery-backed CMOSRAM. Features include an alarm function, programmable peri-odic interrupt and a 100-year calendar. All battery-backedCMOS RAM data remains stored in an additional EEPROM.This prevents data loss in case the cPCI-3920 is operated with-out battery.Counter/TimerThree 8254-style counter/timers are included on the cPCI-3920as defined for the PC/AT (System Timer, Refresh Request,Speaker Tone Output).In addition to the three 8254-style counters, the IICH includesthree High Precision Event Timers (HPET) that may be used bythe operating system. They are implemented as a singlecounter each with its own comparator and value register.They support One-shot and periodic interrupts.Watchdog TimerThe cPCI-3920 provides a Watchdog Timer that is programmablefor a timeout period ranging from 1 ms to 1050 sec. Failure to trig-ger the Watchdog Timer in time results in a system reset, an inter-rupt, or NMI. In the dual-stage mode, a combination of both NMI,and reset if the Watchdog is not serviced. A hardware status flagwill be provided to determine if the Watchdog Timer generated thereset.