Datasheet

TMC429 DATASHEET (v. 1.07 / 2012-AUG-01) 5
Copyright © 2010-2012, TRINAMIC Motion Control GmbH & Co. KG
Figure 3-3: TMC429 application environment with TMC429 in SSOP16 package
10K
SCK_S
SDO_S
SDI_S
nSCS_S
nSCS
SDI
SCK
nSCS
SDI
SCK
nSCS
SDI
SCK
Driver
w/o SDO
Driver
w/o SDO

REF2 REF3
REF1
TEST
GND
µC
SCK
MOSI
MISO
SS
SDI_C
nSCS_C
SCK_C
SDO_C
CLK
CLK
V5V33
470 nF
+5 V
SM#3 SM#2 SM#1
TMC429-LI /
TMC429-PI24
nSCS2
nSCS3
SDO
V5 GND
Note: output SDO_C will
nerver be high impedance
Driver
w/o SDO
Figure 3-4: Usage of drivers without serial data output (SDO) with TMC429 in larger packages
3.1 Step Frequencies
The maximum SPI
TM
data rate is the clock frequency divided by 16. The maximum step frequency
depends on the total length of the datagrams sent to the SPI
TM
stepper motor driver chain. At a clock
frequency of 16 MHz, with a daisy chain of three SPI
TM
stepper motor drivers of 16 bit datagram length
each, the maximum full step frequency is 16 MHz / 16 / ( 3 * 16 ). This is approximately 20 kHz and
that is much higher than needed for typical stepper motors. But, the micro step rate may be higher,
even if the stepper motor driver does not see all micro steps due to SPI
TM
data rate limit, as long as the
number of skipped micro steps is less than a full step. In this respect, one should remember, that at
high step rates respectively pulse rates the differences between micro stepping and full step
excitation vanishes.
3.2 Modes of Motion
The TMC429 has four different modes of motion, programmable individually for each stepper motor,
named RAMP_MODE, SOFT_MODE, VELOCITY_MODE, and HOLD_MODE. For positioning
applications the RAMP_MODE is most suitable, whereas for constant velocity applications the
VELOCITY_MODE is. In RAMP_MODE, the user just sets the position and the TMC429 calculates a
trapezoidal velocity profile and drives autonomously to the target position. During motion, the position
may be altered arbitrarily. The SOFT_MODE is similar to the RAMP_MODE, but the decrease of the
10K
SCK_S
SDO_S
SDI_S
nSCS_S
SDO
CSN
SDI
SCK
SDO
CSN
SDI
SCK
SDO
CSN
SDI
SCK
TMC23x / TMC24x TMC23x / TMC24x TMC23x / TMC24x
REF2 REF3
REF1
TEST GND
µC
SCK
MOSI
MISO
SS
SDI_C
nSCS_C
SCK_C
SDO_C
CLK
CLK
V5V33
470
nF
+5 V
1K 1K
Reference Switch Inputs
(active high)
SM#3 SM#2 SM#1
TMC429-I
1K
100 nF
*For details concerning electrical connections of
the TMC26x refer to its datasheet.
* * *
Note: output SDO_C will
nerver be high impedance