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Re: Regarding to eCos on VRC4373
- To: "Jonathan Larmour" <jlarmour at redhat dot com>, "eCos discussion" <ecos-discuss at sources dot redhat dot com>
- Subject: Re: [ECOS] Regarding to eCos on VRC4373
- From: "Ling Su" <lingsu at palmmicro dot com>
- Date: Wed, 10 Jan 2001 14:07:57 -0800
- Organization: Palm Microsystems, Inc.
- References: <006401c07a8f$c6c9f490$0201a8c0@raccoon> <3A5BB04A.38F502F8@redhat.com> <005e01c07ad5$5ba58210$0301a8c0@leopard> <3A5C9902.4BE2B9F7@redhat.com>
- Reply-To: "Ling Su" <lingsu at palmmicro dot com>
> It is in clock ticks, which are platform-specific. You can use the kernel
> API functions at
> http://sources.redhat.com/ecos/docs-latest/ref/ecos-ref.9.html
>
> Specifically, look at the definition of cyg_resolution_t, and notice you
> can use cyg_clock_get_resolution( cyg_real_time_clock ) to get a
> cyg_resolution_t for your real-time-clock.
>
> A shortcut given that you know the platform is to look at the CDL for the
> vrc4373 which includes the fields CYGNUM_HAL_RTC_NUMERATOR and
> CYGNUM_HAL_RTC_DENOMINATOR which correspond to the fields in the
> cyg_resolution_t. This is 1000000000 and 100 respectively, giving
> 10,000,000 ns/tick == 10 ms/tick.
>
Thanks, Jifl,
If I need a timer faster than 10ms/tick, could I increase denominator or
decrease the numerator? I can it is a caculated value, user can not specify.
How could I change them and what is the consequences?
Regards,
-Ling