ADLINK Technology cPCI-3920 Series, User Manual

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28 Functional Description
3.2 Peripherals
The following standard peripherals are available on the cPCI-3920
board:
Timer
The cPCI-3920 is equipped with the following timers:
Real-Time Clock
The IICH contains real-time clock with 256-byte of battery-
backed RAM.
The real-time clock performs timekeeping functions and
includes 256 bytes of general purpose battery-backed CMOS
RAM. Features include an alarm function, programmable peri-
odic interrupt and a 100-year calendar. All battery-backed
CMOS RAM data remains stored in an additional EEPROM.
This prevents data loss in case the cPCI-3920 is operated with-
out battery.
Counter/Timer
Three 8254-style counter/timers are included on the cPCI-3920
as defined for the PC/AT (System Timer, Refresh Request,
Speaker Tone Output).
In addition to the three 8254-style counters, the IICH includes
three High Precision Event Timers (HPET) that may be used by
the operating system. They are implemented as a single
counter each with its own comparator and value register.
They support One-shot and periodic interrupts.
Watchdog Timer
The cPCI-3920 provides a Watchdog Timer that is programmable
for 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 flag
will be provided to determine if the Watchdog Timer generated the
reset.