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 
Position Comparison of Internal Values
TMC4361A provides several ways of comparing internal values. The position comparison
process is permanently active and associated with one flag and one event. A positive
comparison result can be forwarded through the INTR pin using the POS_COMP_REACHED
event as interrupt source or by using the TARGET_REACHED pin as explained in section 8.4.2,
page 63.
How to compare the internal position with an arbitrary value:
Action:
 Select a comparison value in the POS_COMP register 0x32.
 Select pos_comp_source = 0 ( REFERENCE_CONF register 0x01).
Result:
XACTUAL is compared with POS_COMP . When POS_COMP equals XACTUAL the
POS_COMP_REACHED_F lag becomes set and the POS_COMP_REACHED event
becomes released.
How to compare the external position with an arbitrary value:
Action:
 Select a comparison value in the POS_COMP register 0x32.
 Select pos_comp_source = 1 ( REFERENCE _CONF register 0x01).
Result:
ENC_POS is compared with POS_COMP . When POS_COMP equals ENC_POS the
POS_COMP_REACHED_F lag becomes set and the POS_COMP_REACHED event
becomes released.
NOTE:
 Because ENC_POS represents microsteps and not encoder steps, POS_COMP
represents also microsteps for the comparison process with external positions.
 In case ENC_POS moves past POS_COMP without assuming the same value as
POS_COMP, the POS_COMP_REACHED event is not flagged but is nonetheless
listed in the EVENTS register in order to indicate that it has traversed.
In addition to comparing XACTUAL / ENC_POS with POS_COMP , it is also possible to
conduct a comparison of one of both parameters with X_HOME or X_LATCH resp.
ENC_LATCH . TMC4361A also allows comparison of the revolution counter REV_CNT
against POS_COMP .
Only the selected combination generates the POS_COMP_REACHED_ Flag
and the corresponding event. Therefore, select modified_pos_compare in
the REFERENCE_CONF register 0x01 as outlined in the table below:
Basic
Comparison
Settings
Select External
Position as
Comparison
Base
Comparison
selection grid
SETTINGS
ALERT
!
Comparison Selection Grid
pos_comp_source
modified_pos_compare
‘0’
‘1’
‘00’
XACTUAL vs. POS_COMP
ENC_POS vs. POS_COMP
‘01’
XACTUAL vs. X_HOME
ENC_POS vs. X_HOME
‘10’
XACTUAL vs . X_LATCH
ENC_POS vs. ENC_LATCH
‘11’
REV_CNT vs. POS_COMP
Table 27: Comparison Selection Grid to generate POS_COMP_REACHED_Flag