33970 Datasheet, PDF (26/36 Pages) Freescale Semiconductor, Inc – Dual Gauge Driver Integrated Circuit with Improved Damping Algorithms

FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Table 21. Velocity Table (continued)
Velocity Time Between Velocity
Position
Steps (µs) (µSteps/s)
42
555
1801.8
43
546
1831.5
44
538
1858.7
45
529
1890.4
46
521
1919.4
47
514
1945.5
48
507
1972.4
49
500
2000.0
50
493
2028.4
51
487
2053.4
52
481
2079.0
53
475
2105.3
54
469
2132.2
55
464
2155.2
56
458
2183.4
57
453
2207.5
58
448
2232.1
59
444
2252.3
60
439
2277.9
61
434
2304.1
62
430
2325.6
63
426
2347.4
64
422
2369.7
65
418
2392.3
66
414
2415.5
67
410
2439.0
68
406
2463.1
69
403
2481.4
70
399
2506.3
71
396
2525.3
72
393
2544.5
73
389
2570.7
74
386
2590.7
75
383
2611.0
Velocity Time Between Velocity
Position Steps (µs) (µSteps/s)
118
295
3389.8
119
294
3401.4
120
293
3413.0
121
291
3436.4
122
290
3448.3
123
289
3460.2
124
287
3484.3
125
286
3496.5
126
285
3508.8
127
284
3521.1
128
282
3546.1
129
281
3558.7
130
280
3571.4
131
279
3584.2
132
278
3597.1
133
277
3610.1
134
275
3636.4
135
274
3649.6
136
273
3663.0
137
272
3676.5
138
271
3690.0
139
270
3703.7
140
269
3717.5
141
268
3731.3
142
267
3745.3
143
266
3759.4
144
265
3773.6
145
264
3787.9
146
263
3802.3
147
262
3816.8
148
261
3831.4
149
260
3846.2
150
259
3861.0
151
258
3876.0
Velocity Time Between Velocity
Position Steps (µs) (µSteps/s)
194
226
4424.8
195
225
4444.4
196
224
4464.3
197
224
4464.3
198
223
4484.3
199
222
4504.5
200
222
4504.5
201
221
4524.9
202
221
4524.9
203
220
4545.5
204
220
4545.5
205
219
4566.2
206
218
4587.2
207
218
4587.2
208
217
4608.3
209
217
4608.3
210
216
4629.6
211
216
4629.6
212
215
4651.2
213
215
4651.2
214
214
4672.9
215
214
4672.9
216
213
4694.8
217
212
4717.0
218
212
4717.0
219
211
4739.3
220
211
4739.3
221
210
4761.9
222
210
4761.9
223
209
4784.7
224
209
4784.7
225
208
4807.7
INTERNAL CLOCK CALIBRATION
Timing-related functions on the 33970 (e.g., pointer
velocities, acceleration, and Return To Zero Pointer speeds)
depend upon a precise, consistent time reference to control
the pointer accurately and reliably. Generating accurate time
references on an integrated circuit can be accomplished;
however, they tend to be costly due to the large amount of die
area required for trim pads and the associated trim
procedure. One possibility is an externally generated clock
signal; however, this requires a dedicated pin on the device
and controller. Another expensive approach would require
the use of an additional crystal or resonator.
The internal clock in the 33970 is temperature
independent and area efficient; however, it can vary up to 70
33970
26
Analog Integrated Circuit Device Data
Freescale Semiconductor