Timers — Use of on-chip timers
The eCos kernel system clock is implemented using EPIT1 By
default, the system clock interrupts once every 10ms,
corresponding to a 100Hz clock. This can be changed by the
which corresponds to the clock frequency. Other clock-related
settings are recalculated automatically if the denominator is
changed. If the desired frequency cannot be expressed accurately
solely with changes to
CYGNUM_HAL_RTC_DENOMINATOR, then the
may also be adjusted and the value of
CYGNUM_HAL_RTC_PERIOD adjusted to match.
The same timer is used to implement the HAL microsecond delay
HAL_DELAY_US. This is used by some
device drivers, and in non-kernel configurations such as with
RedBoot where this timer is needed for loading program images via
X/Y-modem protocols and debugging via TCP/IP. Standalone
applications which require RedBoot services, such as debugging,
should avoid use of this timer.
Timer-based profiling support
Timer-based profiling support is implemented using EPIT2 If the
included in the configuration, then EPIT2 reserved for
use by the profiler.
|2019-09-17||eCosPro Non-Commercial Public License|