User`s manual

24 Functional Description
3.2 Peripherals
The following standard peripherals are available on the CT-30
board:
Timer
The CT-30 is equipped with the following timers:
Real-Time Clock
The real-time clock performs timekeeping functions and
includes 256 bytes of general purpose CMOS RAM. Features
include an alarm function, programmable periodic interrupt and
a 100-year calendar. All CMOS RAM data remains stored in an
additional EEPROM to prevent data loss.
Counter/Timer
Three 8254-style counter/timers are included on the CT-30 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 CT-30 provides a Watchdog Timer that is programmable for a
timeout period ranging from 1 ms to 1050 sec. Failure to trigger
the Watchdog Timer in time results in a system reset, an interrupt,
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.