Datasheet

TMC4361A Datasheet | Document Revision 1.22 • 2017-JAN-12
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Read entire documentation; especially the “Supplemental Directives” on page 224.
 MAIN MANUAL 
Because SPI current data is transmitted, automatic switchover from microsteps to
fullsteps and vice versa entirely depends on internal ramp velocity.
In order to activate automatic switchover between microstep and fullstep
operation, do as follows:
Action:
 Set FS_VEL register 0x60 according to the absolute velocity [pps] at which the
switchover should happen.
 Set fs_en = 1 (bit19 of GENERAL_CONF register 0x00).
Result:
Now, current values are switched to fullstep values, in case | VACTUAL |≥ FS_VEL .
A switchback from fullsteps to µsteps is executed, in case | VACTUAL |< FS_VEL .
The status bit FS_ACTIVE is set active as long as fullstep mode is enabled and
activated.
In S/D mode, switchover from microsteps to fullsteps and vice versa is not only
dependent on internal ramp velocity but also on the microstep position of the TMC26x
MSLUT; because switching to a lower resolution must be executed carefully to catch
the correct microstep position. Proper setting of read selection bits for TMC26x stepper
drivers TMC4361A is required to execute switchover automatically.
In order to activate automatic switchover between microstep and fullstep
operation in TMC26x S/D mode, do as follows:
PRECONDITION:
Mandatory TMC26x configuration MUST be executed via cover datagrams:
 Set RDSEL1 = 0 and RDSEL0 = 0 @TMC26x.
Action:
 Set disable_polling = 0 (bit6 of SPI_OUT_CONF register 0x04).
 Set FS_VEL register 0x60 according to the absolute switching velocity [pps].
 Set fs_en = 1 (bit19 of GENERAL_CONF register 0x00).
 Set fs_sdout = 0 (bit20 of GENERAL_CONF register 0x00).
Result:
The µstep resolution of TMC26x is set to fullsteps, in case | VACTUAL | ≥ FS_VEL .
A switchback from fullsteps to µsteps is executed in case | VACTUAL | < FS_VEL .
FS_ACTIVE is set active as long as fullstep mode is enabled and activated.
Presettings of the TMC26x DRVCTRL register – that is executed beforehand via cover
datagrams – are considered whenever the particular register is overwritten with a
newly assigned microstep resolution.
 Turn page for information on changing current scaling parameters for TMC26x in
S/D mode.
TMC26x
SPI Mode:
Automatic
Fullstep
Switchover
TMC26x S/D
Mode: Automatic
Fullstep
Switchover