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Clocks on EDB7XXX
- To: "'eCos Discussion'" <ecos-discuss at sourceware dot cygnus dot com>
- Subject: [ECOS] Clocks on EDB7XXX
- From: "Trenton D. Adams" <tadams at extremeeng dot com>
- Date: Tue, 17 Jul 2001 11:40:48 -0600
- Organization: Extreme Engineering
Ok, the RTC on this platform is 1Hz. If I use cyg_clock_create () will
it always work with the resolution I pass to it? I want to be able to
get a clock based on ms rather than seconds. Also is there a way of
getting the uptime of the system in ms?
What I actually need is a way of getting an accurate time in ms. I was
thinking of doing the following.
On startup do the following
Store the current clock tick value in an initial clock tick variable.
Ultimately I would like this to be in ms and not necessarily clock
ticks.
Store the RTC value in an initial RTC variable
Calculating RTC seconds + ms of time.
Since the RTC is in seconds, I have to make sure the tick variable
before is synchronized with the RTC so 0 ms is at the right time (same
time as an RTC increment).
RTC - RTC variable = seconds since startup
Get tick count
ms = (tick count - tick variable) - seconds since startup * 1000
ms would then be the correct number of milliseconds after the last RTC
increment occurred.
Is there an easier way of doing this in eCos?