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Add support for lo- and hi-res RTC hardware

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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4005 42af7a65-404d-4744-a932-0658087f49c3
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patacongo 2011-10-01 22:09:00 +00:00
parent ea0f852c45
commit 360b2d795d
1 changed files with 53 additions and 14 deletions
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67
Documentation/NuttxPortingGuide.html
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@ -12,7 +12,7 @@
<h1><big><font color="#3c34ec">
<i>NuttX RTOS Porting Guide</i>
</font></big></h1>
<p>Last Updated: September 13, 2011</p>
<p>Last Updated: October 1, 2011</p>
</td>
</tr>
</table>
@ -1989,18 +1989,30 @@ CONFIG_SYSTEM_UTC=y
<h4>4.1.20.2 Hardware</h4>
<p>
To enable hardware module use option:
To enable hardware module use the following configuration options:
<p>
<ul><pre>
CONFIG_RTC=y
</pre></ul>
<ul><dl>
<dt><code>CONFIG_RTC</code>
<dd>Enables general support for a hardware RTC.
Specific architectures may require other specific settings.
<dt><code>CONFIG_RTC_HIRES</code>
<dd>The typical RTC keeps time to resolution of 1 second, usually supporting a 32-bit <code>time_t</code> value.
In this case, the RTC is used to &quot;seed&quot; the normal NuttX timer and the NuttX timer provides for higher resoution time.
If <code>CONFIG_RTC_HIRES</code> is enabled in the NuttX configuration, then the RTC provides higher resolution time and completely replaces the system timer for purpose of date and time.
<dt><code>CONFIG_RTC_FREQUENCY</code>
<dd>If <code>CONFIG_RTC_HIRES</code> is defined, then the frequency of the high resolution RTC must be provided.
If <code>CONFIG_RTC_HIRES</code> is not defined, <code>CONFIG_RTC_FREQUENCY</code> is assumed to be one.
<dt><code>CONFIG_RTC_ALARM</code>
<dd>Enable if the RTC hardware supports setting of an alarm.
A callback function will be executed when the alarm goes off
</dl></ul>
<p>
which requires the following three base functions to read time:
</p>
<ul>
<li><code>up_rtcinitialize()</code></li>
<li><code>up_rtc_gettime()</code>. UTC time in seconds.</li>
<li><code>up_rtc_getclock()</code>. Replacement for <code>g_system_tick</code></li>
<li><code>up_rtc_time()</code>. UTC time in seconds.</li>
<li><code>up_rtc_gettime()</code>. Replacement for <code>g_system_tick</code></li>
</ul>
<p>
This module depends on <code>CONFIG_SYSTEM_UTC=y</code>.
@ -2024,15 +2036,17 @@ CONFIG_RTC=y
Running at rate of system base timer, used for time-slicing, and so forth.
</p>
<p>
If hardware RTC is present (<code>CONFIG_RTC</code>) and enabled, then after successful
initiliazation variables are overriden by calls to <code>up_rtc_getclock()</code> which is
If hardware RTC is present (<code>CONFIG_RTC</code>) and and high-resolution timeing
is enabled (<code>CONFIG_RTC_HIRES</code>), then after successful
initiliazation variables are overriden by calls to <code>up_rtc_gettime()</code> which is
running continously even in power-down modes.
</p>
<p>
In the case of <code>CONFIG_RTC</code> is set the <code>g_tickcount</code> and <code>g_system_utc</code> keep
counting at rate of a system timer, which however, is disabled in power-down
mode. By comparing this time and RTC (actual time) one may determine the
actual system active time. To retrieve that variable use:
In the case of <code>CONFIG_RTC_HIRES</code> is set the <code>g_tickcount</code> and
<code>g_system_utc</code> keep counting at rate of a system timer, which however, is
disabled in power-down mode.
By comparing this time and RTC (actual time) one may determine the actual system active time.
To retrieve that variable use:
</p>
<ul><pre>
<li><code>clock_gettime(CLOCK_ACTIVETIME, tp)</code>
@ -4239,10 +4253,35 @@ build
</ul>
<h2>Device Drivers</h2>
<h3>RTC</h3>
<ul>
<li>
<code>CONFIG_RTC</code>:
Enables general support for a hardware RTC.
Specific architectures may require other specific settings.
</li>
<li>
<code>CONFIG_RTC_HIRES</code>:
The typical RTC keeps time to resolution of 1 second, usually supporting a 32-bit <code>time_t</code> value.
In this case, the RTC is used to &quot;seed&quot; the normal NuttX timer and the NuttX timer provides for higher resoution time.
If <code>CONFIG_RTC_HIRES</code> is enabled in the NuttX configuration, then the RTC provides higher resolution time and completely replaces the system timer for purpose of date and time.
</li>
<li>
<code>CONFIG_RTC_FREQUENCY</code>:
If <code>CONFIG_RTC_HIRES</code> is defined, then the frequency of the high resolution RTC must be provided.
If <code>CONFIG_RTC_HIRES</code> is not defined, <code>CONFIG_RTC_FREQUENCY</code> is assumed to be one.
</li>
<li>
<code>CONFIG_RTC_ALARM</code>:
Enable if the RTC hardware supports setting of an alarm.
A callback function will be executed when the alarm goes off
</li>
</ul>
<h3>SPI driver</h3>
<ul>
<li>
<code>CONFIG_SPI_OWNBUS</code> - Set if there is only one active device
<code>CONFIG_SPI_OWNBUS</code>: Set if there is only one active device
on the SPI bus. No locking or SPI configuration will be performed.
It is not necessary for clients to lock, re-configure, etc..
</li>