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 
12. NFREEZE and Emergency Stop
In case dysfunctions at board level occur, some applications require an additional strategy to
end current operations without any delay. Therefore, TMC4361A provides the low active safety
pin NFREEZE.
NFREEZE is low active. An active NFREEZE input transition from high to low level stops
the current ramp immediately in a user configured way.
At the moment - when NFREEZE switches to low - an event FROZEN is triggered at
EVENTS (10). FROZEN remains active until the reset of the TMC4361A.
It is necessary to tie NFREEZE low for at least three clock cycles because of
the input filter of three consecutive sample points.
Pin Description: NFREEZE
Pin Name
Type
Remarks
NFREEZE
Input
External enable pin; low active.
Table 49: Pin Description: NFREEZE
Pin Descriptions: DFREEZE and IFREEZE
Register Name
Register Address
Remarks
DFREEZE
0x4E (23:0)
RW
Deceleration value in the case of an active FREEZE event.
IFREEZE
0x4E (31:24)
RW
Current scaling value in the case of an active FREEZE event.
Table 50: Pin Descriptions DFREEZE and IFREEZE
Two parameters ( DFREEZE and IFREEZE ) are necessary in order to be able to use the
TMC4361A freeze function. They are integrated in the freeze register, which can be
written only once after an active reset; assuming that there has not been a
ramp start before. Thus, the freeze parameters should be set directly before
operation.
NOTE:
 Selected values cannot be altered until the next active reset. These restrictions
are necessary to protect the TMC4361A freeze configuration from incorrect SPI
data sent from the microcontroller in case of error.
Keep in mind that:
 The polarity of NFREEZE input cannot be assigned.
 The freeze register can always be read out.
 During freeze state, ramp register values can be read out.
NFREEZE
Operational
Principle
AREAS OF
SPECIAL
CONCERN
!
Configuration of
FREEZE Function
AREAS OF
SPECIAL
CONCERN
!