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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2008-01-11 18:19:09 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2008-01-11 18:19:09 +0000 |
commit | 3b0eb489665d4d8422d34309a13b20fcf65f637a (patch) | |
tree | 865e706cf0ed1dbe84005bee16774f4f97055b4b /nuttx/arch/z16/src/common/up_udelay.c | |
parent | ddfaa63ee4ff54b4f875b33cc62823fe73419164 (diff) | |
download | px4-nuttx-3b0eb489665d4d8422d34309a13b20fcf65f637a.tar.gz px4-nuttx-3b0eb489665d4d8422d34309a13b20fcf65f637a.tar.bz2 px4-nuttx-3b0eb489665d4d8422d34309a13b20fcf65f637a.zip |
untest z16f code
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@553 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/arch/z16/src/common/up_udelay.c')
-rw-r--r-- | nuttx/arch/z16/src/common/up_udelay.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/nuttx/arch/z16/src/common/up_udelay.c b/nuttx/arch/z16/src/common/up_udelay.c new file mode 100644 index 000000000..18b176302 --- /dev/null +++ b/nuttx/arch/z16/src/common/up_udelay.c @@ -0,0 +1,132 @@ +/**************************************************************************** + * common/up_udelay.c + * + * Copyright (C) 2008 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> +#include <nuttx/arch.h> + +#ifdef CONFIG_BOARD_LOOPSPERMSEC + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +#define CONFIG_BOARD_LOOPSPER100USEC ((CONFIG_BOARD_LOOPSPERMSEC+5)/10) +#define CONFIG_BOARD_LOOPSPER10USEC ((CONFIG_BOARD_LOOPSPERMSEC+50)/100) +#define CONFIG_BOARD_LOOPSPERUSEC ((CONFIG_BOARD_LOOPSPERMSEC+500)/1000) + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: up_udelay + * + * Description: + * Delay inline for the requested number of microseconds. NOTE: Because + * of all of the setup, several microseconds will be lost before the actual + * timing looop begins. Thus, the delay will always be a few microseconds + * longer than requested. + * + * *** NOT multi-tasking friendly *** + * + * ASSUMPTIONS: + * The setting CONFIG_BOARD_LOOPSPERMSEC has been calibrated + * + ****************************************************************************/ + +void up_udelay(unsigned int microseconds) +{ + volatile int i; + + /* We'll do this a little at a time because we expect that the + * CONFIG_BOARD_LOOPSPERUSEC is very inaccurate during to truncation in + * the divisions of its calculation. We'll use the largest values that + * we can in order to prevent significant error buildup in the loops. + */ + + while (microseconds > 1000) + { + for (i = 0; i < CONFIG_BOARD_LOOPSPERMSEC; i++) + { + } + microseconds -= 1000; + } + + while (microseconds > 100) + { + for (i = 0; i < CONFIG_BOARD_LOOPSPER100USEC; i++) + { + } + microseconds -= 100; + } + + while (microseconds > 10) + { + for (i = 0; i < CONFIG_BOARD_LOOPSPER10USEC; i++) + { + } + microseconds -= 10; + } + + while (microseconds > 0) + { + for (i = 0; i < CONFIG_BOARD_LOOPSPERUSEC; i++) + { + } + microseconds--; + } +} +#endif /* CONFIG_BOARD_LOOPSPERMSEC */ + |