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Fix numerous typos in configuration variable names. Tracked down by Alan Carvalho de Assis

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This commit is contained in:
Gregory Nutt 2015-05-23 17:08:35 -06:00
parent 32dcac3ab9
commit 33790f4d16
3 changed files with 10 additions and 10 deletions
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2
Documentation/NXGraphicsSubsystem.html
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@ -3464,7 +3464,7 @@ int nxf_convert_32bpp(FAR uint32_t *dest, uint16_t height,
By default, keyboard input is taken from stdin (<code>/dev/console</code>).
If this option is set, then the interface<code>nxterm_kdbin()</code> is enabled.
That interface may be driven by window callback functions so that keyboard input <i>only</i> goes to the top window.
<dt><code>CONFIG__NXTERM_KBDBUFSIZE</code>:
<dt><code>CONFIG_NXTERM_KBDBUFSIZE</code>:
<dd>If <code>CONFIG_NXTERM_NXKBDIN</code> is enabled, then this value may be used to
define the size of the per-window keyboard input buffer. Default: 16
<dt><code>CONFIG_NXTERM_NPOLLWAITERS</code>:

16
Documentation/NuttxPortingGuide.html
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@ -2257,23 +2257,23 @@ The system can be re-made subsequently by just typing <code>make</code>.
<p><b>System Timer</b>
In most implementations, system time is provided by a timer interrupt.
That timer interrupt runs at rate determined by <code>CONFIG_USEC_PER_TICKS</code> (default 10000 microseconds or 100Hz. If <code>CONFIG_SCHED_TICKLESS</code> is selected, the default is 100 microseconds).
The timer generates an interrupt each <code>CONFIG_USEC_PER_TICKS</code> microseconds and increments a counter called <code>g_system_timer</code>.
<code>g_system_timer</code> then provides a time-base for calculating <i>up-time</i> and elapsed time intervals in units of <code>CONFIG_USEC_PER_TICKS</code>.
That timer interrupt runs at rate determined by <code>CONFIG_USEC_PER_TICK</code> (default 10000 microseconds or 100Hz. If <code>CONFIG_SCHED_TICKLESS</code> is selected, the default is 100 microseconds).
The timer generates an interrupt each <code>CONFIG_USEC_PER_TICK</code> microseconds and increments a counter called <code>g_system_timer</code>.
<code>g_system_timer</code> then provides a time-base for calculating <i>up-time</i> and elapsed time intervals in units of <code>CONFIG_USEC_PER_TICK</code>.
The range of <code>g_system_timer</code> is, by default, 32-bits.
However, if the MCU supports type <code>long long</code> and <code>CONFIG_SYSTEM_TIME16</code> is selected,
a 64-bit system timer will be supported instead.
</p>
<p><b>System Timer Accuracy</b>
On many system, the exact timer interval specified by <code>CONFIG_USEC_PER_TICKS</code> cannot be achieved due to limitations in frequencies or in dividers.
As a result, the time interval specified by <code>CONFIG_USEC_PER_TICKS</code> may only be approximate and there may be small errors in the apparent <i>up-time</i> time.
On many system, the exact timer interval specified by <code>CONFIG_USEC_PER_TICK</code> cannot be achieved due to limitations in frequencies or in dividers.
As a result, the time interval specified by <code>CONFIG_USEC_PER_TICK</code> may only be approximate and there may be small errors in the apparent <i>up-time</i> time.
These small errors, however, will accumulate over time and after a long period of time may have an unacceptably large error in the apparent <i>up-time</i> of the MCU.
</p>
If the timer tick period generated by the hardware is not exactly <code>CONFIG_USEC_PER_TICKS</code> <i>and</i> if there you require accurate up-time for the MCU, then there are measures that you can take:
If the timer tick period generated by the hardware is not exactly <code>CONFIG_USEC_PER_TICK</code> <i>and</i> if there you require accurate up-time for the MCU, then there are measures that you can take:
</p>
<ul>
<li>
Perhaps you can adjust <code>CONFIG_USEC_PER_TICKS</code> to a different value so that an exactly <code>CONFIG_USEC_PER_TICKS</code> can be realized.
Perhaps you can adjust <code>CONFIG_USEC_PER_TICK</code> to a different value so that an exactly <code>CONFIG_USEC_PER_TICK</code> can be realized.
</li>
<li>
Or you can use a technique known as <i>Delta-Sigma Modulation</i>. (Suggested by Uros Platise). Consider the example below.
@ -2284,7 +2284,7 @@ The system can be re-made subsequently by just typing <code>make</code>.
Consider this case: The system timer is a count-up timer driven at 32.768KHz.
There are dividers that can be used, but a divider of one yields the highest accuracy.
This counter counts up until the count equals a match value, then a timer interrupt is generated.
The desire frequency is 100Hz (<code>CONFIG_USEC_PER_TICKS</code> is 10000).
The desire frequency is 100Hz (<code>CONFIG_USEC_PER_TICK</code> is 10000).
</p>
<p>
This exact frequency of 100Hz cannot be obtained in this case.

2
Documentation/NuttxUserGuide.html
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@ -4729,7 +4729,7 @@ Differences from the POSIX implementation include:
</li>
<li>
All <code>sa_flags</code> in struct sigaction of act input are ignored (all treated like <code>SA_SIGINFO</code>).
The one exception is if <code>CONFIG_SCHED_CHILDSTATUS</code> is defined;
The one exception is if <code>CONFIG_SCHED_CHILD_STATUS</code> is defined;
then <code>SA_NOCLDWAIT</code> is supported but only for <code>SIGCHLD</code>.
</li>
</ul>