Mercurial > public > ostc4
view Discovery/Inc/crcmodel.h @ 329:da5b91b1e20e I2C_Improvment
Improved startup robustness
The firmware implements a 30 minute delay for surface pressure values. This array might be corrupted if first pressure communication fails => only init array if initialization was successfull
| author | ideenmodellierer |
|---|---|
| date | Wed, 17 Jul 2019 22:42:55 +0200 |
| parents | 5f11787b4f42 |
| children | 45b8f3c2acce |
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/////////////////////////////////////////////////////////////////////////////// /// -*- coding: UTF-8 -*- /// /// \file Discovery/Inc/crcmodel.h /// \brief Rocksoft CRC Model Algorithm /// \author Ross Williams (ross@guest.adelaide.edu.au.) and Heinrichs Weikamp /// \date 3 June 1993 /// /// \details /// /// This is the header (.h) file for the reference /// implementation of the Rocksoft^tm Model CRC Algorithm. For more /// information on the Rocksoft^tm Model CRC Algorithm, see the document /// titled "A Painless Guide to CRC Error Detection Algorithms" by Ross /// Williams (ross@guest.adelaide.edu.au.). This document is likely to be in /// "ftp.adelaide.edu.au/pub/rocksoft". /// /// Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia. /// /// $Id$ /////////////////////////////////////////////////////////////////////////////// /// \par Copyright (c) 2014-2018 Heinrichs Weikamp gmbh /// /// This program is free software: you can redistribute it and/or modify /// it under the terms of the GNU General Public License as published by /// the Free Software Foundation, either version 3 of the License, or /// (at your option) any later version. /// /// This program is distributed in the hope that it will be useful, /// but WITHOUT ANY WARRANTY; without even the implied warranty of /// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the /// GNU General Public License for more details. /// /// You should have received a copy of the GNU General Public License /// along with this program. If not, see <http://www.gnu.org/licenses/>. ////////////////////////////////////////////////////////////////////////////// /******************************************************************************/ /* Start of crcmodel.h */ /******************************************************************************/ /* */ /* Author : Ross Williams (ross@guest.adelaide.edu.au.). */ /* Date : 3 June 1993. */ /* Status : Public domain. */ /* */ /* Description : This is the header (.h) file for the reference */ /* implementation of the Rocksoft^tm Model CRC Algorithm. For more */ /* information on the Rocksoft^tm Model CRC Algorithm, see the document */ /* titled "A Painless Guide to CRC Error Detection Algorithms" by Ross */ /* Williams (ross@guest.adelaide.edu.au.). This document is likely to be in */ /* "ftp.adelaide.edu.au/pub/rocksoft". */ /* */ /* Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia. */ /* */ /******************************************************************************/ /* */ /* How to Use This Package */ /* ----------------------- */ /* Step 1: Declare a variable of type cm_t. Declare another variable */ /* (p_cm say) of type p_cm_t and initialize it to point to the first */ /* variable (e.g. p_cm_t p_cm = &cm_t). */ /* */ /* Step 2: Assign values to the parameter fields of the structure. */ /* If you don't know what to assign, see the document cited earlier. */ /* For example: */ /* p_cm->cm_width = 16; */ /* p_cm->cm_poly = 0x8005L; */ /* p_cm->cm_init = 0L; */ /* p_cm->cm_refin = TRUE; */ /* p_cm->cm_refot = TRUE; */ /* p_cm->cm_xorot = 0L; */ /* Note: Poly is specified without its top bit (18005 becomes 8005). */ /* Note: Width is one bit less than the raw poly width. */ /* */ /* Step 3: Initialize the instance with a call cm_ini(p_cm); */ /* */ /* Step 4: Process zero or more message bytes by placing zero or more */ /* successive calls to cm_nxt. Example: cm_nxt(p_cm,ch); */ /* */ /* Step 5: Extract the CRC value at any time by calling crc = cm_crc(p_cm); */ /* If the CRC is a 16-bit value, it will be in the bottom 16 bits. */ /* */ /******************************************************************************/ /* */ /* Design Notes */ /* ------------ */ /* PORTABILITY: This package has been coded very conservatively so that */ /* it will run on as many machines as possible. For example, all external */ /* identifiers have been restricted to 6 characters and all internal ones to */ /* 8 characters. The prefix cm (for Crc Model) is used as an attempt to avoid */ /* namespace collisions. This package is endian independent. */ /* */ /* EFFICIENCY: This package (and its interface) is not designed for */ /* speed. The purpose of this package is to act as a well-defined reference */ /* model for the specification of CRC algorithms. If you want speed, cook up */ /* a specific table-driven implementation as described in the document cited */ /* above. This package is designed for validation only; if you have found or */ /* implemented a CRC algorithm and wish to describe it as a set of parameters */ /* to the Rocksoft^tm Model CRC Algorithm, your CRC algorithm implementation */ /* should behave identically to this package under those parameters. */ /* */ /******************************************************************************/ #ifndef CRC_MODEL_H #define CRC_MODEL_H /******************************************************************************/ /* The following definitions are extracted from my style header file which */ /* would be cumbersome to distribute with this package. The DONE_STYLE is the */ /* idempotence symbol used in my style header file. */ #ifndef DONE_STYLE typedef unsigned long ulong; typedef unsigned bool; typedef unsigned char * p_ubyte_; #ifndef TRUE #define FALSE 0 #define TRUE 1 #endif /* Change to the second definition if you don't have prototypes. */ #define P_(A) A /* #define P_(A) () */ /* Uncomment this definition if you don't have void. */ /* typedef int void; */ #endif /******************************************************************************/ /* CRC Model Abstract Type */ /* ----------------------- */ /* The following type stores the context of an executing instance of the */ /* model algorithm. Most of the fields are model parameters which must be */ /* set before the first initializing call to cm_ini. */ typedef struct { int cm_width; /* Parameter: Width in bits [8,32]. */ ulong cm_poly; /* Parameter: The algorithm's polynomial. */ ulong cm_init; /* Parameter: Initial register value. */ bool cm_refin; /* Parameter: Reflect input bytes? */ bool cm_refot; /* Parameter: Reflect output CRC? */ ulong cm_xorot; /* Parameter: XOR this to output CRC. */ ulong cm_reg; /* Context: Context during execution. */ } cm_t; typedef cm_t *p_cm_t; /******************************************************************************/ /* Functions That Implement The Model */ /* ---------------------------------- */ /* The following functions animate the cm_t abstraction. */ void cm_ini P_((p_cm_t p_cm)); /* Initializes the argument CRC model instance. */ /* All parameter fields must be set before calling this. */ void cm_nxt P_((p_cm_t p_cm,int ch)); /* Processes a single message byte [0,255]. */ void cm_blk P_((p_cm_t p_cm,p_ubyte_ blk_adr,ulong blk_len)); /* Processes a block of message bytes. */ ulong cm_crc P_((p_cm_t p_cm)); /* Returns the CRC value for the message bytes processed so far. */ /******************************************************************************/ /* Functions For Table Calculation */ /* ------------------------------- */ /* The following function can be used to calculate a CRC lookup table. */ /* It can also be used at run-time to create or check static tables. */ ulong cm_tab P_((p_cm_t p_cm,int index)); /* Returns the i'th entry for the lookup table for the specified algorithm. */ /* The function examines the fields cm_width, cm_poly, cm_refin, and the */ /* argument table index in the range [0,255] and returns the table entry in */ /* the bottom cm_width bytes of the return value. */ /******************************************************************************/ #endif // CRC_MODEL_H