General-purpose timers — Use of IXP4xx general-purpose timers
General-purpose timer 0
The IXP4xx processor HAL provides general-purpose timer 0
OST_TIM0) to the eCos kernel for use as a real-time clock.
This timer is also used for implementing the
functionality, which 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.
General-purpose timer 1 and the timestamp timer are available for application use.
System clock configuration
By default for eCos applications, the system clock interrupts
once every 10ms, corresponding to a 100Hz clock. This can be changed by
the configuration option
CYGNUM_HAL_RTC_DENOMINATOR 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 configuration
CYGNUM_HAL_RTC_NUMERATOR may also be
adjusted, and again clock-related settings will automatically be
|2018-07-27||eCosPro Non-Commercial Public License|