From 2a6a151342905377c60711c1cade166ffa058e86 Mon Sep 17 00:00:00 2001 From: Lorenz Meier Date: Mon, 27 Aug 2012 22:55:19 +0200 Subject: Added common conversion functions --- apps/systemlib/conversions.c | 57 +++++++++++++++++++++++++++++++++++++++++ apps/systemlib/conversions.h | 61 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 118 insertions(+) create mode 100644 apps/systemlib/conversions.c create mode 100644 apps/systemlib/conversions.h diff --git a/apps/systemlib/conversions.c b/apps/systemlib/conversions.c new file mode 100644 index 000000000..99ee41508 --- /dev/null +++ b/apps/systemlib/conversions.c @@ -0,0 +1,57 @@ +/**************************************************************************** + * + * Copyright (C) 2012 PX4 Development Team. All rights reserved. + * Author: @author Lorenz Meier + * + * 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 PX4 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. + * + ****************************************************************************/ + +/** + * @file conversions.c + * Implementation of commonly used conversions. + */ + +#include +#include + +#include "conversions.h" + +int16_t +int16_t_from_bytes(uint8_t bytes[]) +{ + union { + uint8_t b[2]; + int16_t w; + } u; + + u.b[1] = bytes[0]; + u.b[0] = bytes[1]; + + return u.w; +} diff --git a/apps/systemlib/conversions.h b/apps/systemlib/conversions.h new file mode 100644 index 000000000..dc383e770 --- /dev/null +++ b/apps/systemlib/conversions.h @@ -0,0 +1,61 @@ +/**************************************************************************** + * + * Copyright (C) 2012 PX4 Development Team. All rights reserved. + * Author: Lorenz Meier + * + * 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 PX4 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. + * + ****************************************************************************/ + +/** + * @file conversions.h + * Definition of commonly used conversions. + * + * Includes bit / byte / geo representation and unit conversions. + */ + +#ifndef CONVERSIONS_H_ +#define CONVERSIONS_H_ +#include +#include + +__BEGIN_DECLS + +/** + * Converts a signed 16 bit integer from big endian to little endian. + * + * This function is for commonly used 16 bit big endian sensor data, + * delivered by driver routines as two 8 bit numbers in big endian order. + * Common vendors with big endian representation are Invense, Bosch and + * Honeywell. ST micro devices tend to use a little endian representation. + */ +__EXPORT int16_t int16_t_from_bytes(uint8_t bytes[]); + +__END_DECLS + +#endif /* CONVERSIONS_H_ */ -- cgit v1.2.3