User Manual

TMC5031-EVAL Manual / Firmware V1.00 (Rev. 1.00 / 2013-FEB-22) 23
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0X6C, 0X7C: CHOPCONF – CHOPPER CONFIGURATION
Bit
Name
Function
Comment
19
vhighchm
high velocity chopper
mode
This bit enables switching to chm=1 and fd=0, when
VHIGH is exceeded. This way, a higher velocity can be
achieved. Can be combined with vhighfs=1. If set, the
TOFF setting automatically becomes doubled during
high velocity operation in order to avoid doubling of
the chopper frequency.
18
vhighfs
high velocity fullstep
selection
This bit enables switching to fullstep, when VHIGH is
exceeded. Switching takes place only at 45° position.
The fullstep target current uses the current value from
the microstep table at the 45° position.
17
vsense
sense resistor voltage
based current scaling
0: Low sensitivity, high sense resistor voltage
1: High sensitivity, low sense resistor voltage
16
tbl1
TBL
blank time select
%00 … %11:
Set comparator blank time to 16, 24, 36 or 54 clocks
Hint: %10 is recommended for most applications
15
tbl0
14
chm
chopper mode
0
Standard mode (spreadCycle)
1
Constant off time with fast decay time.
Fast decay time is also terminated when the
negative nominal current is reached. Fast decay is
after on time.
13
rndtf
random TOFF time
0
Chopper off time is fixed as set by TOFF
1
Random mode, TOFF is random modulated by
d
NCLK
= -12 … +3 clocks.
12
disfdcc
fast decay mode
chm=1:
disfdcc=1 disables current comparator usage for termi-
nation of the fast decay cycle
11
fd3
TFD [3]
chm=1:
MSB of fast decay time setting TFD
10
hend3
HEND
hysteresis low value
OFFSET
sine wave offset
chm=0
%0000 … %1111:
Hysteresis is -3, -2, -1, 0, 1, …, 12
(1/512 of this setting adds to current setting)
This is the hysteresis value which becomes
used for the hysteresis chopper.
9
hend2
8
hend1
7
hend0
chm=1
%0000 … %1111:
Offset is -3, -2, -1, 0, 1, …, 12
This is the sine wave offset and 1/512 of the
value becomes added to the absolute value
of each sine wave entry.
6
hstrt2
HSTRT
hysteresis start value
added to HEND
chm=0
%000 … %111:
Add 1, 2, …, 8 to hysteresis low value HEND
(1/512 of this setting adds to current setting)
Attention: Effective HEND+HSTRT ≤ 16.
Hint: Hysteresis decrement is done each 16
clocks
5
hstrt1
4
hstrt0
TFD [2..0]
fast decay time setting
chm=1
Fast decay time setting (MSB: fd3):
%0000 … %1111:
Fast decay time setting TFD with
NCLK= 32*HSTRT (%0000: slow decay only)
3
toff3
TOFF off time
and driver enable
Off time setting controls duration of slow decay phase
NCLK= 12 + 32*TOFF
%0000: Driver disable, all bridges off
%0001: 1 – use only with TBL ≥ 2
%0010 … %1111: 2 … 15
2
toff2
1
toff1
0
toff0
Table 6.5 Abridgement of CHOPCONF register