WebSVN – libIgnTiming – Blame – /trunk/src/timing.cpp

Rev	Author	Line No.	Line
2	mjames	1	#include <cstdint>
		2	#include <assert.h>
		3	#include "libIgnTiming/timing.h"
11	mjames	4
		5	#if !defined WRITABLE_TABLE
		6	#define CONST_ATTR constexpr
		7	#endif
		8
7	mjames	9	#if defined __cplusplus
		10	extern "C"
2	mjames	11	{
7	mjames	12	#endif
2	mjames	13
7	mjames	14	namespace
		15	{
11	mjames	16	int8_t timingAdjust = 0 * TIMING_SCALE; // in TIMING_SCALE
2	mjames	17
7	mjames	18	unsigned constexpr INTERP_SCALE = 256;
2	mjames	19
7	mjames	20	int constexpr TimingScale = TIMING_SCALE;
		21	int16_t constexpr NO_DATA = -1;
6	mjames	22
11	mjames	23	int16_t constexpr MAX_ADVANCE = 50 * TIMING_SCALE;
		24	int16_t constexpr MIN_ADVANCE = 7 * TIMING_SCALE;
2	mjames	25
7	mjames	26	// array of column headings
11	mjames	27	int16_t CONST_ATTR rpmMap[MAX_RPM_POINTS] = {400, 750, 1000, 1500, 2500, 3500, 4500, 6000};
		28	// column of row values - in 1000-pressure
		29	int16_t CONST_ATTR vacuumMap[MAX_VACUUM_POINTS] = {0, 166, 225, 300, 700, 1000, NO_DATA, NO_DATA};
		30	uint8_t CONST_ATTR mapping[MAX_VACUUM_POINTS][MAX_RPM_POINTS] = {
7	mjames	31	/* Table in degrees. */
		32	/* row for 0mb = centrifugal only */
		33	{12, 7, 7, 19, 25, 29, 29, 22},
		34	/* row for 166 mB*/
		35	{12, 7, 7, 21, 27, 31, 31, 24},
		36	/* row for 225 mB */
		37	{12, 7, 7, 25, 31, 35, 35, 28},
		38	/* row for 300 mB*/
		39	{12, 7, 7, 29, 35, 39, 39, 33},
		40	/* row for 700 mB*/
11	mjames	41	{12, 7, 7, 19, 25, 29, 29, 22},
7	mjames	42	/* row for 1000 mB - used when pressure drops off the scale */
		43	{7, 7, 7, 7, 7, 7, 7, 7},
		44	/* unused */
		45	{0, 0, 0, 0, 0, 0, 0, 0},
		46	/* unused */
		47	{0, 0, 0, 0, 0, 0, 0, 0},
		48	/* unused */
2	mjames	49
7	mjames	50	};
6	mjames	51
7	mjames	52	}
6	mjames	53
7	mjames	54	uint8_t getTimingAdjust() { return timingAdjust; };
6	mjames	55
7	mjames	56	void setTimingAdjust(int8_t adjust) { timingAdjust = adjust; }
6	mjames	57
7	mjames	58	int16_t getRpmMap(unsigned int i)
		59	{
		60	if (i >= 0 && i < MAX_RPM_POINTS)
		61	return rpmMap[i];
		62	else
		63	return 0;
		64	}
6	mjames	65
7	mjames	66	void setRpmMap(unsigned int i, uint16_t val)
		67	{
11	mjames	68	#if WRITABLE_TABLE
7	mjames	69	if (i >= 0 && i < MAX_RPM_POINTS)
		70	rpmMap[i] = val;
11	mjames	71	#endif
7	mjames	72	}
6	mjames	73
7	mjames	74	uint16_t getVacuumMap(unsigned int i)
		75	{
		76	if (i >= 0 && i < MAX_VACUUM_POINTS)
		77	return vacuumMap[i];
		78	else
		79	return 0;
		80	}
6	mjames	81
7	mjames	82	void setVacuumMap(unsigned int i, uint16_t val)
		83	{
11	mjames	84	#if WRITABLE_TABLE
7	mjames	85	if (i >= 0 && i < MAX_VACUUM_POINTS)
		86	vacuumMap[i] = val;
11	mjames	87	#endif
7	mjames	88	}
6	mjames	89
7	mjames	90	void setTiming(unsigned int vacuumIndex, unsigned int rpmIndex, uint8_t value)
2	mjames	91	{
11	mjames	92
		93	#if WRITABLE_TABLE
7	mjames	94	if (vacuumIndex < 0 && vacuumIndex >= MAX_VACUUM_POINTS)
		95	return;
		96	if (rpmIndex < 0 && rpmIndex >= MAX_RPM_POINTS)
		97	return;
		98	mapping[vacuumIndex][rpmIndex] = value;
11	mjames	99	#endif
2	mjames	100	}
		101
7	mjames	102	uint8_t getTiming(unsigned int vacuumIndex, unsigned int rpmIndex)
2	mjames	103	{
7	mjames	104	if (vacuumIndex < 0 && vacuumIndex >= MAX_VACUUM_POINTS)
		105	return 0;
		106	if (rpmIndex < 0 && rpmIndex >= MAX_RPM_POINTS)
		107	return 0;
		108	return mapping[vacuumIndex][rpmIndex];
2	mjames	109	}
7	mjames	110
11	mjames	111	/// @brief Lookup a point in a 1 dimensional array -
		112	/// @param point Value to lookup
		113	/// @param curve Lookup table
		114	/// @param size Size of lookup table
		115	/// @param [out] frac fraction of distance from first point in array
		116	/// @return index in array or NO_DATA if operations fail
7	mjames	117	int lookup(int point, int16_t const curve[], int size, int16_t *frac)
2	mjames	118	{
7	mjames	119	// check lower bounds
		120	if (point < curve[0])
2	mjames	121	{
7	mjames	122	*frac = 0;
		123	return 0;
		124	}
		125	// check upper bounds
		126	// find the upper boundary by looking for non -1 points
		127	int upper = size - 1;
8	mjames	128	while (upper != 0 && curve[upper] == NO_DATA)
7	mjames	129	upper--;
2	mjames	130
7	mjames	131	if (point >= curve[upper])
		132	{
		133	*frac = 0;
		134	return upper;
		135	}
		136	for (int pt = 1; pt <= upper; pt++)
		137	{
		138	if ((point >= curve[pt - 1]) && (point < curve[pt]))
		139	{
2	mjames	140
7	mjames	141	int range1 = curve[pt] - curve[pt - 1];
2	mjames	142
7	mjames	143	if (range1 == 0)
		144	{
		145	*frac = 0;
		146	return pt - 1;
		147	}
		148
		149	// how far along axis ?
		150	int offset = point - curve[pt - 1];
		151
		152	int range2 = INTERP_SCALE;
		153
		154	frac = ((offset range2) / range1);
		155	return pt - 1;
		156	}
2	mjames	157	}
7	mjames	158	*frac = 0;
11	mjames	159	return NO_DATA; // give up.
7	mjames	160	};
2	mjames	161
7	mjames	162	extern "C"
2	mjames	163	{
		164
7	mjames	165	int mapTiming(int rpm, int vacuumMb)
		166	{
		167	int angle = 0;
		168	/* lookup the interpolated RPM point */
		169	int16_t rpm_frac = 0;
		170	int rpm_index = lookup(rpm, rpmMap, MAX_RPM_POINTS, &rpm_frac);
		171	if (rpm_index == NO_DATA)
		172	return timingAdjust + MIN_ADVANCE;
2	mjames	173
7	mjames	174	/* lookup the interpolated vacuum point */
		175	int16_t vacuum_frac = 0;
		176	int vacuum_index = lookup(vacuumMb, vacuumMap, MAX_VACUUM_POINTS, &vacuum_frac);
		177	/* if there is a problem, bail out */
		178	if (vacuum_index == NO_DATA)
		179	return timingAdjust + MIN_ADVANCE;
2	mjames	180
7	mjames	181	/* perform a bilinear mapping */
		182	int top_advance;
		183	// we now have a position between two points in X and Y
		184	if (rpm_frac == 0)
		185	top_advance = mapping[vacuum_index][rpm_index] * INTERP_SCALE;
		186	// if fractional part then interpolate points off the map
		187	else
		188	top_advance = mapping[vacuum_index][rpm_index] * (INTERP_SCALE - rpm_frac) + mapping[vacuum_index][rpm_index + 1] * rpm_frac;
		189
		190	int bottom_advance;
		191	// if no fractional part, then the top and bottom advance point is the same
		192	if (vacuum_frac == 0)
		193	{
		194	angle = top_advance * TimingScale / INTERP_SCALE;
		195	}
		196	else
		197	{
		198	bottom_advance = mapping[vacuum_index + 1][rpm_index] * (INTERP_SCALE - rpm_frac) + mapping[vacuum_index + 1][rpm_index + 1] * rpm_frac;
		199	/* interpolate down Y axis this time */
		200	int advance = top_advance * (INTERP_SCALE - vacuum_frac) + bottom_advance * vacuum_frac;
		201	/* point is scaled by two multiplications */
		202	angle = advance * TimingScale / (INTERP_SCALE * INTERP_SCALE);
		203	}
		204
		205	if (angle < MIN_ADVANCE)
		206	angle = MIN_ADVANCE;
		207	if (angle > MAX_ADVANCE)
		208	angle = MAX_ADVANCE;
		209
		210	return angle + timingAdjust;
2	mjames	211	}
		212	}
7	mjames	213	#if defined __cplusplus
2	mjames	214	}
7	mjames	215	#endif

Subversion Repositories libIgnTiming

(root)/trunk/src/timing.cpp – Rev 11