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

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(root)/trunk/src/timing.cpp – Rev 7