— eCos Support for the Kinetis on-chip Watchdog timer device (WDOG)
The Freescale Kinetis processor provides a Watchdog Timer (WDOG) module. Once the watchdog timer is enabled it will automatically reset the processor unless software resets the timer within the configured period.
provides an eCos driver for this device, complementing the generic
CYGPKG_IO_WATCHDOG. The functionality should be
accessed via the standard eCos watchdog functions
The driver only supports “reset” mode.
The Kinetis watchdog driver package should be loaded automatically
when selecting a platform containing a Kinetis processor, and it
should never be necessary to load it explicitly into the
configuration. The package is inactive unless the generic watchdog
CYGPKG_IO_WATCHDOG is loaded and the
watchdog explicitly started. Depending on the choice of eCos template
it may be necessary to load the
package. By default the HAL startup for the Kinetis platform disables
the watchdog shortly after reset, so even when the I/O watchdog
package is loaded the watchdog will not trigger unless the watchdog
support is explicitly started by
The package provides four main configuration options.
CYGIMP_WATCHDOG_HARDWARE can be used to disable the
use of the hardware watchdog and switch to a software emulation
provided by the generic watchdog package instead. This may prove
useful during debugging.
CYGNUM_DEVS_WATCHDOG_CORTEXM_KINETIS_CLK is used to
select the clock source used to drive the watchdog timer module. The
setting of this variable affects the minimum and maximum values that
can be configured for the watchdog timeout.
can further extend the maximum possible value for the watchdog
determines the timeout before the hardware watchdog resets the system.
The default setting gives a 1-second timeout. The minimum and maximum
timeout values are determined by the selected source clock and
prescaler values. Depending on the configuration the range can extend
from 9 microseconds to 4000 seconds.
The watchdog device driver does not require any platform-specific
support. The only porting effort required is to list
CYGPKG_DEVICES_WATCHDOG_CORTEXM_KINETIS as one of the hardware
packages in the ecos.db target entry.
|2018-07-27||eCosPro Non-Commercial Public License|