TMC428_06 Datasheet, PDF (42/58 Pages) List of Unclassifed Manufacturers – Intelligent Triple Stepper Motor Controller with Serial Peripheral Interfaces

TMC428 DATASHEET (v. 2.02 / April 26^th, 2006)
42
Hints: One should always initialize the whole LUT to be sure to read valid wave values, even if one
changes the micro step resolution after some micro steps have been done on higher resolution. Even if
one uses e.g. 16 times microstepping, one gets a smoother move for the stepper motor if one
initializes the full sine wave LUT according to Table 12-2 - Datagrams for initialization of a quarter sine
wave period microstep look-up-table on page 40 and using the MSB DAC bits (DAC_A_5, DAC_A_4,
DAC_A_3, DAC_A_2 and DAC_B_5, DAC_B_4, DAC_B_3, DAC_B_2). So, one should always
completely initialize the quarter sine wave LUT, no matter what micro step resolution is used. The
addressing starts at 0 after power-on reset only. Changing the micro step resolution after some micro
steps have been made causes an offset for the addressing that has to be taken into account for
positioning a stepper motor.
usrs
increment
width
%110
1
sin
cos
%101
2
sin
cos
%100
4
sin
cos
%011
8
sin
cos
%010
16
sin
cos
%001
(HS)
32
sin
cos
%000
(FS)
64
sin
cos
1^st quadrant
0,1,2, 3, ..., 61, 62,63,
63, 63, 62, 61,...,2,1,
0,2, 4, 6, ..., 58, 60,62,
63, 60, 58, 56,..., 4, 2,
0, 4, 8, 12, ..., 56, 60,
63, 60, 56, ..., 12, 8, 4,
0, 8, 16, 24, ... , 48, 56
63, 56, 48, 40,...,16, 8,
0, 16, 32, 48,
63, 48, 32, 16,
0, 32,
63, 32,
0,
63,
2^nd quadrant
63, 63, 62, 61,..., 3, 2,1,
0,1,2, 3, ..., 61, 62,63,
63, 60, 58, 56,..., 4, 2,
0,2, 4, 6, ..., 58, 60,62,
63, 60, 56, ..., 12, 8, 4,
0, 4, 8, 12, ..., 56, 60,
63, 56, 48, 40,...,16, 8,
0, 8, 16, 24, ... , 48, 56
63, 48, 32, 16,
0, 16, 32, 48,
63, 32,
0, 32,
63,
0,
3^rd quadrant
0,1,2, 3, ..., 61, 62,63,
63, 63,62,61,...,3, 2,1,
0,2, 4, 6, ..., 58, 60,62,
63, 60, 58, 56,..., 4, 2,
0, 4, 8, 12, ..., 56, 60,
63, 60, 56, ..., 12, 8, 4,
0, 8, 16, 24, ... , 48, 56
63, 56, 48, 40,...,16, 8,
0, 16, 32, 48,
63, 48, 32, 16,
0, 32,
63, 32
0,
63
4^th quadrant
63, 63,62,61,..., 3, 2,1
0,1,2, 3, ..., 61, 62,63
63, 60, 58, 56,..., 4, 2
0,2, 4, 6, ..., 58, 60,62
63, 60, 56, ..., 12, 8, 4
0, 4, 8, 12, ..., 56, 60
63, 56, 48, 40,...,16, 8
0, 8, 16, 24, ... , 48, 56
63, 48, 32, 16
0, 16, 32, 48
63, 32
0, 32
63
0
Table 12-4: Wave look-up table (LUT) indices for different microstep resolutions
12.2 Partial look-up table initialization option
A partially initialized micro step table may be sufficient, if all stepper motors– except those driven in full
step mode –are programmed to use the same micro step resolution constantly before a single micro
step is processed. But with a partial initialized micro step look-up table, the micro step resolution must
not be changed after any step is made after power-on reset. So, a partially initialized look-up table
should be taken into account only, if it is a must because of too small memory of the host
microcontroller. Instead of partial initialization of the look-up table of the TMC428, initialization with a
triangular function f_rhomb(ϕ) would be a better choice.
Copyright © 2004-2006, TRINAMIC Motion Control GmbH & Co. KG