TMC5161 DATASHEET (Rev. 1.01 / 2018-NOV-20)
102
When the microstep sequencer advances within the table, it calculates the actual current values for
the motor coils with each microstep and stores them to the registers CUR_A and CUR_B. However the
incremental coding requires an absolute initialization, especially when the microstep table becomes
modified. Therefore CUR_A and CUR_B become initialized whenever MSCNT passes zero.
Two registers control the starting values of the tables:
-
As the starting value at zero is not necessarily 0 (it might be 1 or 2), it can be programmed
into the starting point register START_SIN.
-
In the same way, the start of the second wave for the second motor coil needs to be stored
in START_SIN90. This register stores the resulting table entry for a phase shift of 90° for a 2-
phase motor.
Hint
Refer chapter 6.5 for the register set and for the default table function stored in the drivers. The
default table is a good base for realizing an own table.
The TMC5161-EVAL comes with a calculation tool for own waves.
Initialization example for the default microstep table:
MSLUT[0]= %10101010101010101011010101010100 = 0xAAAAB554
MSLUT[1]= %01001010100101010101010010101010 = 0x4A9554AA
MSLUT[2]= %00100100010010010010100100101001 = 0x24492929
MSLUT[3]= %00010000000100000100001000100010 = 0x10104222
MSLUT[4]= %11111011111111111111111111111111 = 0xFBFFFFFF
MSLUT[5]= %10110101101110110111011101111101 = 0xB5BB777D
MSLUT[6]= %01001001001010010101010101010110 = 0x49295556
MSLUT[7]= %00000000010000000100001000100010 = 0x00404222
MSLUTSEL= 0xFFFF8056:
X1=128, X2=255, X3=255
W3=%01, W2=%01, W1=%01, W0=%10
MSLUTSTART= 0x00F70000:
START_SIN_0= 0, START_SIN90= 247
19 Emergency Stop
The driver provides a negative active enable pin ENN to safely switch off all power MOSFETs. This
allows putting the motor into freewheeling. Further, it is a safe hardware function whenever an
emergency-stop not coupled to software is required. Some applications may require the driver to be
put into a state with active holding current or with a passive braking mode. This is possible by
programming the pin ENCA_DCIN to act as a step disable function. Set GCONF flag stop_enable to
activate this option. Whenever ENCA_DCIN becomes pulled up, the motor will stop abruptly and go to
the power down state, as configured via IHOLD, IHOLDDELAY and stealthChop standstill options.
Disabling the driver via ENN will require three clock cycles to safely switch off the driver.
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