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Odometry/QEI/QEI.h@0:b127c787a51b, 2015-05-24 (annotated)

Committer:: Jagang
Date:: Sun May 24 12:30:47 2015 +0000
Revision:: 0:b127c787a51b

Nettoyage du code d'asserv.; L'asserv ne fonctionne plus, juste test, moteurs ? 20% sur 1m

Who changed what in which revision?

User	Revision	Line number	New contents of line
Jagang	0:b127c787a51b	1	/**
Jagang	0:b127c787a51b	2	* @author Aaron Berk
Jagang	0:b127c787a51b	3	*
Jagang	0:b127c787a51b	4	* @section LICENSE
Jagang	0:b127c787a51b	5	*
Jagang	0:b127c787a51b	6	* Copyright (c) 2010 ARM Limited
Jagang	0:b127c787a51b	7	*
Jagang	0:b127c787a51b	8	* Permission is hereby granted, free of charge, to any person obtaining a copy
Jagang	0:b127c787a51b	9	* of this software and associated documentation files (the "Software"), to deal
Jagang	0:b127c787a51b	10	* in the Software without restriction, including without limitation the rights
Jagang	0:b127c787a51b	11	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
Jagang	0:b127c787a51b	12	* copies of the Software, and to permit persons to whom the Software is
Jagang	0:b127c787a51b	13	* furnished to do so, subject to the following conditions:
Jagang	0:b127c787a51b	14	*
Jagang	0:b127c787a51b	15	* The above copyright notice and this permission notice shall be included in
Jagang	0:b127c787a51b	16	* all copies or substantial portions of the Software.
Jagang	0:b127c787a51b	17	*
Jagang	0:b127c787a51b	18	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
Jagang	0:b127c787a51b	19	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
Jagang	0:b127c787a51b	20	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
Jagang	0:b127c787a51b	21	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
Jagang	0:b127c787a51b	22	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
Jagang	0:b127c787a51b	23	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
Jagang	0:b127c787a51b	24	* THE SOFTWARE.
Jagang	0:b127c787a51b	25	*
Jagang	0:b127c787a51b	26	* @section DESCRIPTION
Jagang	0:b127c787a51b	27	*
Jagang	0:b127c787a51b	28	* Quadrature Encoder Interface.
Jagang	0:b127c787a51b	29	*
Jagang	0:b127c787a51b	30	* A quadrature encoder consists of two code tracks on a disc which are 90
Jagang	0:b127c787a51b	31	* degrees out of phase. It can be used to determine how far a wheel has
Jagang	0:b127c787a51b	32	* rotated, relative to a known starting position.
Jagang	0:b127c787a51b	33	*
Jagang	0:b127c787a51b	34	* Only one code track changes at a time leading to a more robust system than
Jagang	0:b127c787a51b	35	* a single track, because any jitter around any edge won't cause a state
Jagang	0:b127c787a51b	36	* change as the other track will remain constant.
Jagang	0:b127c787a51b	37	*
Jagang	0:b127c787a51b	38	* Encoders can be a homebrew affair, consisting of infrared emitters/receivers
Jagang	0:b127c787a51b	39	* and paper code tracks consisting of alternating black and white sections;
Jagang	0:b127c787a51b	40	* alternatively, complete disk and PCB emitter/receiver encoder systems can
Jagang	0:b127c787a51b	41	* be bought, but the interface, regardless of implementation is the same.
Jagang	0:b127c787a51b	42	*
Jagang	0:b127c787a51b	43	* +-----+ +-----+ +-----+
Jagang	0:b127c787a51b	44	* Channel A \| ^ \| \| \| \| \|
Jagang	0:b127c787a51b	45	* ---+ ^ +-----+ +-----+ +-----
Jagang	0:b127c787a51b	46	* ^ ^
Jagang	0:b127c787a51b	47	* ^ +-----+ +-----+ +-----+
Jagang	0:b127c787a51b	48	* Channel B ^ \| \| \| \| \| \|
Jagang	0:b127c787a51b	49	* ------+ +-----+ +-----+ +-----
Jagang	0:b127c787a51b	50	* ^ ^
Jagang	0:b127c787a51b	51	* ^ ^
Jagang	0:b127c787a51b	52	* 90deg
Jagang	0:b127c787a51b	53	*
Jagang	0:b127c787a51b	54	* The interface uses X2 encoding by default which calculates the pulse count
Jagang	0:b127c787a51b	55	* based on reading the current state after each rising and falling edge of
Jagang	0:b127c787a51b	56	* channel A.
Jagang	0:b127c787a51b	57	*
Jagang	0:b127c787a51b	58	* +-----+ +-----+ +-----+
Jagang	0:b127c787a51b	59	* Channel A \| \| \| \| \| \|
Jagang	0:b127c787a51b	60	* ---+ +-----+ +-----+ +-----
Jagang	0:b127c787a51b	61	* ^ ^ ^ ^ ^
Jagang	0:b127c787a51b	62	* ^ +-----+ ^ +-----+ ^ +-----+
Jagang	0:b127c787a51b	63	* Channel B ^ \| ^ \| ^ \| ^ \| ^ \| \|
Jagang	0:b127c787a51b	64	* ------+ ^ +-----+ ^ +-----+ +--
Jagang	0:b127c787a51b	65	* ^ ^ ^ ^ ^
Jagang	0:b127c787a51b	66	* ^ ^ ^ ^ ^
Jagang	0:b127c787a51b	67	* Pulse count 0 1 2 3 4 5 ...
Jagang	0:b127c787a51b	68	*
Jagang	0:b127c787a51b	69	* This interface can also use X4 encoding which calculates the pulse count
Jagang	0:b127c787a51b	70	* based on reading the current state after each rising and falling edge of
Jagang	0:b127c787a51b	71	* either channel.
Jagang	0:b127c787a51b	72	*
Jagang	0:b127c787a51b	73	* +-----+ +-----+ +-----+
Jagang	0:b127c787a51b	74	* Channel A \| \| \| \| \| \|
Jagang	0:b127c787a51b	75	* ---+ +-----+ +-----+ +-----
Jagang	0:b127c787a51b	76	* ^ ^ ^ ^ ^
Jagang	0:b127c787a51b	77	* ^ +-----+ ^ +-----+ ^ +-----+
Jagang	0:b127c787a51b	78	* Channel B ^ \| ^ \| ^ \| ^ \| ^ \| \|
Jagang	0:b127c787a51b	79	* ------+ ^ +-----+ ^ +-----+ +--
Jagang	0:b127c787a51b	80	* ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
Jagang	0:b127c787a51b	81	* ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
Jagang	0:b127c787a51b	82	* Pulse count 0 1 2 3 4 5 6 7 8 9 ...
Jagang	0:b127c787a51b	83	*
Jagang	0:b127c787a51b	84	* It defaults
Jagang	0:b127c787a51b	85	*
Jagang	0:b127c787a51b	86	* An optional index channel can be used which determines when a full
Jagang	0:b127c787a51b	87	* revolution has occured.
Jagang	0:b127c787a51b	88	*
Jagang	0:b127c787a51b	89	* If a 4 pules per revolution encoder was used, with X4 encoding,
Jagang	0:b127c787a51b	90	* the following would be observed.
Jagang	0:b127c787a51b	91	*
Jagang	0:b127c787a51b	92	* +-----+ +-----+ +-----+
Jagang	0:b127c787a51b	93	* Channel A \| \| \| \| \| \|
Jagang	0:b127c787a51b	94	* ---+ +-----+ +-----+ +-----
Jagang	0:b127c787a51b	95	* ^ ^ ^ ^ ^
Jagang	0:b127c787a51b	96	* ^ +-----+ ^ +-----+ ^ +-----+
Jagang	0:b127c787a51b	97	* Channel B ^ \| ^ \| ^ \| ^ \| ^ \| \|
Jagang	0:b127c787a51b	98	* ------+ ^ +-----+ ^ +-----+ +--
Jagang	0:b127c787a51b	99	* ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
Jagang	0:b127c787a51b	100	* ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
Jagang	0:b127c787a51b	101	* ^ ^ ^ +--+ ^ ^ +--+ ^
Jagang	0:b127c787a51b	102	* ^ ^ ^ \| \| ^ ^ \| \| ^
Jagang	0:b127c787a51b	103	* Index ------------+ +--------+ +-----------
Jagang	0:b127c787a51b	104	* ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
Jagang	0:b127c787a51b	105	* Pulse count 0 1 2 3 4 5 6 7 8 9 ...
Jagang	0:b127c787a51b	106	* Rev. count 0 1 2
Jagang	0:b127c787a51b	107	*
Jagang	0:b127c787a51b	108	* Rotational position in degrees can be calculated by:
Jagang	0:b127c787a51b	109	*
Jagang	0:b127c787a51b	110	* (pulse count / X * N) * 360
Jagang	0:b127c787a51b	111	*
Jagang	0:b127c787a51b	112	* Where X is the encoding type [e.g. X4 encoding => X=4], and N is the number
Jagang	0:b127c787a51b	113	* of pulses per revolution.
Jagang	0:b127c787a51b	114	*
Jagang	0:b127c787a51b	115	* Linear position can be calculated by:
Jagang	0:b127c787a51b	116	*
Jagang	0:b127c787a51b	117	* (pulse count / X * N) * (1 / PPI)
Jagang	0:b127c787a51b	118	*
Jagang	0:b127c787a51b	119	* Where X is encoding type [e.g. X4 encoding => X=44], N is the number of
Jagang	0:b127c787a51b	120	* pulses per revolution, and PPI is pulses per inch, or the equivalent for
Jagang	0:b127c787a51b	121	* any other unit of displacement. PPI can be calculated by taking the
Jagang	0:b127c787a51b	122	* circumference of the wheel or encoder disk and dividing it by the number
Jagang	0:b127c787a51b	123	* of pulses per revolution.
Jagang	0:b127c787a51b	124	*/
Jagang	0:b127c787a51b	125
Jagang	0:b127c787a51b	126	#ifndef QEI_H
Jagang	0:b127c787a51b	127	#define QEI_H
Jagang	0:b127c787a51b	128
Jagang	0:b127c787a51b	129	/**
Jagang	0:b127c787a51b	130	* Includes
Jagang	0:b127c787a51b	131	*/
Jagang	0:b127c787a51b	132	#include "mbed.h"
Jagang	0:b127c787a51b	133
Jagang	0:b127c787a51b	134	/**
Jagang	0:b127c787a51b	135	* Defines
Jagang	0:b127c787a51b	136	*/
Jagang	0:b127c787a51b	137	#define PREV_MASK 0x1 //Mask for the previous state in determining direction
Jagang	0:b127c787a51b	138	//of rotation.
Jagang	0:b127c787a51b	139	#define CURR_MASK 0x2 //Mask for the current state in determining direction
Jagang	0:b127c787a51b	140	//of rotation.
Jagang	0:b127c787a51b	141	#define INVALID 0x3 //XORing two states where both bits have changed.
Jagang	0:b127c787a51b	142
Jagang	0:b127c787a51b	143	/**
Jagang	0:b127c787a51b	144	* Quadrature Encoder Interface.
Jagang	0:b127c787a51b	145	*/
Jagang	0:b127c787a51b	146	class QEI {
Jagang	0:b127c787a51b	147
Jagang	0:b127c787a51b	148	public:
Jagang	0:b127c787a51b	149
Jagang	0:b127c787a51b	150	typedef enum Encoding {
Jagang	0:b127c787a51b	151
Jagang	0:b127c787a51b	152	X2_ENCODING,
Jagang	0:b127c787a51b	153	X4_ENCODING
Jagang	0:b127c787a51b	154
Jagang	0:b127c787a51b	155	} Encoding;
Jagang	0:b127c787a51b	156
Jagang	0:b127c787a51b	157	/**
Jagang	0:b127c787a51b	158	* Constructor.
Jagang	0:b127c787a51b	159	*
Jagang	0:b127c787a51b	160	* Reads the current values on channel A and channel B to determine the
Jagang	0:b127c787a51b	161	* initial state.
Jagang	0:b127c787a51b	162	*
Jagang	0:b127c787a51b	163	* Attaches the encode function to the rise/fall interrupt edges of
Jagang	0:b127c787a51b	164	* channels A and B to perform X4 encoding.
Jagang	0:b127c787a51b	165	*
Jagang	0:b127c787a51b	166	* Attaches the index function to the rise interrupt edge of channel index
Jagang	0:b127c787a51b	167	* (if it is used) to count revolutions.
Jagang	0:b127c787a51b	168	*
Jagang	0:b127c787a51b	169	* @param channelA mbed pin for channel A input.
Jagang	0:b127c787a51b	170	* @param channelB mbed pin for channel B input.
Jagang	0:b127c787a51b	171	* @param index mbed pin for optional index channel input,
Jagang	0:b127c787a51b	172	* (pass NC if not needed).
Jagang	0:b127c787a51b	173	* @param pulsesPerRev Number of pulses in one revolution.
Jagang	0:b127c787a51b	174	* @param encoding The encoding to use. Uses X2 encoding by default. X2
Jagang	0:b127c787a51b	175	* encoding uses interrupts on the rising and falling edges
Jagang	0:b127c787a51b	176	* of only channel A where as X4 uses them on both
Jagang	0:b127c787a51b	177	* channels.
Jagang	0:b127c787a51b	178	*/
Jagang	0:b127c787a51b	179	QEI(PinName channelA, PinName channelB, PinName index, int pulsesPerRev, Encoding encoding = X2_ENCODING);
Jagang	0:b127c787a51b	180
Jagang	0:b127c787a51b	181	/**
Jagang	0:b127c787a51b	182	* Reset the encoder.
Jagang	0:b127c787a51b	183	*
Jagang	0:b127c787a51b	184	* Sets the pulses and revolutions count to zero.
Jagang	0:b127c787a51b	185	*/
Jagang	0:b127c787a51b	186	void reset(void);
Jagang	0:b127c787a51b	187
Jagang	0:b127c787a51b	188	/**
Jagang	0:b127c787a51b	189	* Read the state of the encoder.
Jagang	0:b127c787a51b	190	*
Jagang	0:b127c787a51b	191	* @return The current state of the encoder as a 2-bit number, where:
Jagang	0:b127c787a51b	192	* bit 1 = The reading from channel B
Jagang	0:b127c787a51b	193	* bit 2 = The reading from channel A
Jagang	0:b127c787a51b	194	*/
Jagang	0:b127c787a51b	195	int getCurrentState(void);
Jagang	0:b127c787a51b	196
Jagang	0:b127c787a51b	197	/**
Jagang	0:b127c787a51b	198	* Read the number of pulses recorded by the encoder.
Jagang	0:b127c787a51b	199	*
Jagang	0:b127c787a51b	200	* @return Number of pulses which have occured.
Jagang	0:b127c787a51b	201	*/
Jagang	0:b127c787a51b	202	int getPulses(void);
Jagang	0:b127c787a51b	203
Jagang	0:b127c787a51b	204	/**
Jagang	0:b127c787a51b	205	* Read the number of revolutions recorded by the encoder on the index channel.
Jagang	0:b127c787a51b	206	*
Jagang	0:b127c787a51b	207	* @return Number of revolutions which have occured on the index channel.
Jagang	0:b127c787a51b	208	*/
Jagang	0:b127c787a51b	209	int getRevolutions(void);
Jagang	0:b127c787a51b	210
Jagang	0:b127c787a51b	211
Jagang	0:b127c787a51b	212
Jagang	0:b127c787a51b	213	/**
Jagang	0:b127c787a51b	214	* Update the pulse count.
Jagang	0:b127c787a51b	215	*
Jagang	0:b127c787a51b	216	* Called on every rising/falling edge of channels A/B.
Jagang	0:b127c787a51b	217	*
Jagang	0:b127c787a51b	218	* Reads the state of the channels and determines whether a pulse forward
Jagang	0:b127c787a51b	219	* or backward has occured, updating the count appropriately.
Jagang	0:b127c787a51b	220	*/
Jagang	0:b127c787a51b	221	void encode(void);
Jagang	0:b127c787a51b	222
Jagang	0:b127c787a51b	223	int getPulsesPerRev() {return pulsesPerRev_;}
Jagang	0:b127c787a51b	224	private:
Jagang	0:b127c787a51b	225	/**
Jagang	0:b127c787a51b	226	* Called on every rising edge of channel index to update revolution
Jagang	0:b127c787a51b	227	* count by one.
Jagang	0:b127c787a51b	228	*/
Jagang	0:b127c787a51b	229	void index(void);
Jagang	0:b127c787a51b	230
Jagang	0:b127c787a51b	231	Encoding encoding_;
Jagang	0:b127c787a51b	232
Jagang	0:b127c787a51b	233	InterruptIn channelA_;
Jagang	0:b127c787a51b	234	InterruptIn channelB_;
Jagang	0:b127c787a51b	235	InterruptIn index_;
Jagang	0:b127c787a51b	236
Jagang	0:b127c787a51b	237	int pulsesPerRev_;
Jagang	0:b127c787a51b	238	int prevState_;
Jagang	0:b127c787a51b	239	int currState_;
Jagang	0:b127c787a51b	240
Jagang	0:b127c787a51b	241	volatile int pulses_;
Jagang	0:b127c787a51b	242	volatile int revolutions_;
Jagang	0:b127c787a51b	243
Jagang	0:b127c787a51b	244	};
Jagang	0:b127c787a51b	245
Jagang	0:b127c787a51b	246	#endif /* QEI_H */