Re: [ECOS] role of RTC

[Jonathan Larmour <jlarmour at redhat dot com>]

Arnaud Mouiche wrote:
> 
> we can see that each processor port defines those functions (in the
> 'xxxx_misc.c' file):
> 
> - void hal_clock_initialize(cyg_uint32 period)
> - void hal_clock_read(cyg_uint32 *pvalue)
> - void hal_delay_us(cyg_int32 usecs)
> 
> what kind of timer should a processor use to define correctly those functions ?

One that can deliver a regular interrupt after a specified time.

> what is the link between the RTC and the scheduler. If there is one, where
> is it defined ?

Each platform defines CYGNUM_HAL_INTERRUPT_RTC which indicates which
interrupt is used for the kernel RTC. The kernel then attaches to that
interrupt, initializes the clock with hal_clock_initialize, and then just
has to wait for the interrupts.
 
> where is defined the time slicing of the scheduler ?

kernel/VERSION/src/common/clock.cxx has the real time clock stuff. Look at
the end of the file. The RTC DSR calls the scheduler timeslice function.

Jifl
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