TMC428_06 Datasheet, PDF (39/58 Pages) List of Unclassifed Manufacturers – Intelligent Triple Stepper Motor Controller with Serial Peripheral Interfaces

TMC428 DATASHEET (v. 2.02 / April 26^th, 2006)
39
binary datagram specification : hexadecimal datagram
%10000000----------000101--010000 : $80000510
%10000010----------000011--000100 : $82000304
%10000100----------000110--000010 : $84000602
%10000110----------001101--010000 : $86000D10
%10001000----------001011--001100 : $88000B0C
%10001010----------101110--001010 : $8a002E0A
%10001100----------000101--010000 : $8c000510
%10001110----------000011--000100 : $8e000304
%10010000----------000110--000010 : $90000602
%10010010----------001101--010000 : $92000D10
%10010100----------001011--001100 : $94000B0C
%10010110----------101110--001010 : $96002E0A
%10011000----------000101--000111 : $98000507
%10011010----------000011--000100 : $9a000304
%10011100----------000110--000010 : $9c000602
%10011110----------001101--001111 : $9e000D0F
%10100000----------001011--001100 : $a0000B0C
%10100010----------101110--001010 : $a2002E0A
Table 11-3: Configuration datagram sequence for the example (with '-' (don't cares))
12 Initialization of the Micro Step Look-Up-Table
The TMC428 provides a look-up-table (LUT) of 64 values of 6 bit for micro stepping. The micro step
LUT can be adapted by storing an arbitrary quarter period of a periodic function to match individual
stepper motor characteristics. It is common to use one period of a sine wave function for micro
stepping. With that function, the current of one phase is driven with the sine function whereas the other
phase is driven with the cosine function.
To initialize the LUT for micro stepping one simply has to load a quarter sine wave period into the
micro step LUT. Two successive values of the sine wave function are included in one datagram similar
to the primary signal code words for the stepper motor driver chain configuration. The TMC428
automatically expands the quarter sine wave period to a full sine and cosine function. The necessary
data values y(i) to represent a ¼ sine wave period for the micro step LUT are defined by
y(i) = int[ ½ + 64 * sin(¼ * 2 * π * i / 64) ] with i = { 0, 1, 2, 3, ..., 60, 61, 62, 63 },
where the conditional replacement y(i) := 63 for y(i) > 63 has to be done. The last five values (which
are calculated to be 64) have to be replaced by 63. With this replacement one finally gets y(i) = { 0, 2,
3, 5, 6, 8, 9, 11, 12, 14, 16, 17, 19, 20, 22, 23, 24, 26, 27, 29, 30, 32, 33, 34, 36, 37, 38, 39, 41, 42, 43,
44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 56, 57, 58, 59, 59, 60, 60, 61, 61, 62, 62, 62, 63, 63,
63, 63, 63, 63, 63, 63 }.
32 bit DATAGRAM sent from a µC to the TMC428 via pin SDI_C
3^{3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 9 8 7 6 5 4 3 2 1 0}
1^{0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0}
ADDRESS
11 0 0 0 0 00
00001
00010
00011
00100
DATA
(x)₁₀
2
5
8
11
14
data @ odd
RAM addresses
000010
000101
001000
001011
001110
(x)₁₀
0
3
6
9
12
data @ even
RAM addresses
000000
000011
000110
001001
001100
Copyright © 2004-2006, TRINAMIC Motion Control GmbH & Co. KG