AMIS-30621 LIN Micro-stepping Motor Driver
Data Sheet
LIN Lost During Normal Operation
If the LIN communication is lost during normal operation, it is assumed that AMIS-30621 is referenced. In other words the ActPos
register contains the “real” actual position. At LIN – lost an absolute positioning to the stored secure position SecPos is done. This is
further called secure positioning.
Following sequence will be followed. See Figure 28.
1. “SecPos[10:0]” from RAM register will be used. This can be different from OTP register if earlier LIN master communication
has updated this. See also Secure Position and command SetMotorParam.
2. If the LIN communication is lost there are two possibilities:
I. If SecPos[10:0] = 0x400:
No secure positioning will be performed
AMIS-30621 will enter the SLEEP state
II. If SecPos[10:0] ≠ 0x400:
Perform a secure positioning. This is an absolute positioning (slave knows its ActPos. SecPos[10:0] will be copied in
TagPos).
After the positioning is finished AMIS-30621 will enter the SLEEP state.
Important Remarks:
(1) The secure position has a resolution of 11 bit.
(2) Same behavior in case of HW2 float (= lost LIN address). See also Hardwired Address HW2
A
SetMotorParam
(RAM content is overwritten)
No
LIN bus OK
SecPos = 0x400
Yes
No
Yes
Secure Positioning
to TagPos
Normal Function
SLEEP
SLEEP
PC20070304.4
Figure 28: Case A: LIN Lost During Normal Operation
LIN Lost Before or at Power On
If the LIN communication is lost before or at power on, no correct GetFullStatus command is received. For that reason the ShutDown
state is not left and the stepper motor is kept un-powered.
AMI Semiconductor – Sept. 2007, Rev 1.5
42
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