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Re: Regarding to eCos on VRC4373
- To: Ling Su <lingsu at palmmicro dot com>,eCos discussion <ecos-discuss at sources dot redhat dot com>
- Subject: Re: [ECOS] Regarding to eCos on VRC4373
- From: Jonathan Larmour <jlarmour at redhat dot com>
- Date: Wed, 10 Jan 2001 17:16:50 +0000
- Organization: Red Hat UK Ltd.
- References: <006401c07a8f$c6c9f490$0201a8c0@raccoon> <3A5BB04A.38F502F8@redhat.com> <005e01c07ad5$5ba58210$0301a8c0@leopard>
Ling Su wrote:
>
> Another questions is: What's the time unit used in eCos, in kernel API or
> timer/counter object, such as cyg_thread_delay(time), how to set the delay
> time, it is in microsecond unit or more?
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.
Jifl
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