[ECOS] Regarding to eCos on VRC4373

Jonathan Larmour jlarmour@redhat.com
Wed Jan 10 09:17:00 GMT 2001


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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