Datasheet
TMC429 DATASHEET (v. 1.07 / 2012-AUG-01) 35
Copyright © 2010-2012, TRINAMIC Motion Control GmbH & Co. KG
10.10 Reference Switches l3 & r3 & l2 & r2 & l2 & r1 (JDX=%1110)
The current state of all reference switches demultiplexed internally by the TMC429 if left and right
reference switches are used can be read from this read-only register. The bit named
continuous_update of the Stepper Motor Global Parameter Register (JDX=%1111) is important
for reading out of reference switches as explained below.
10.11 Stepper Motor Global Parameter Register (JDX=%1111)
This register holds different configuration bits for the stepper motor driver chain. The absolute address
(RRS & ADDRESS) of the stepper motor global parameter register is %01111110 = $7E (see Table
8-2, page 18, and Table 10-3, page 35). For the datagram configuration the number of stepper motor
drivers is important. It is represented by the parameter LSMD (Last Stepper Motor Driver). The
parameter LSMD has to be set to %00 for one stepper motor driver, %01 for two stepper motor
drivers, and %10 for three stepper motor drivers (see Table 10-4).
32 bit DATAGRAM sent from a µC to the TMC429
3
1
3
0
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
1
5
1
4
1
3
1
2
1
1
1
0
9
8
7
6
5
4
3
2
1
0
RRS
ADDRESS
RW
DATA
0
1
1
1
1
1
1
clk2_div
polarities
LSMD
mot1r
refmux
continuous_update
csCommonIndividual
polarity_DAC_AB
polarity_FD
polarity_PH_AB
polarity_sck_s
polarity_nscs_s
last stepper motor driver
Table 10-3: Stepper motor global parameter register
LSMD
number of stepper motor drivers
%00 (=0)
1
%01 (=1)
2
%10 (=2)
3
%11 (=3)
NOT ALLOWED
Table 10-4: Global parameter LSMD (last stepper motor driver)
Five bits are used to control signal polarities. The polarity of the selection signal nSCS_S for the
stepper motor driver chain is controlled by the polarity bit polarity_nscs_s. The nSCS_S signal is low
The polarity of the stepper motor driver chain clock signal SCK_S is defined by the bit polarity_sck_s.
Figure 7-3 on page 13. The clock signal SCK_S is
inverted if it is set polarity_PH_AB defines the polarity of the phase bits for the stepper
motor. Inverting this bit changes the rotation direction of the associated stepper motor. The bit
polarity_FD defines the polarity of the fast decay controlling bit. If i