AMIS-30623 LIN Microstepping Motordriver
Data Sheet
16.8.3. Fail Safe Motion
The OTP bit <FailSafe> enables or disables an automatic motion to a predefined safe position. See also Autonomous Motion.
Table 33: Fail Safe Enable Selection
<FailSafe>
Behavior
0
1
NO motion in case of LIN – lost
ENABLES motion to a safe position in case of LIN – lost
16.8.4. Autonomous Motion
AMIS-30623 is able to perform an Autonomous Motion to a preferred position. This positioning starts after the detection of lost LIN
communication and in case:
- the OTP bit <FailSafe> = 1.
- RAM register SecPos[10:0] ≠ 0x400
The functional behavior depends if LIN communication is lost during normal operation (see Figure 27 case A) or at (or before) start-up
(See Figure 27 case B):
Power Up
OTP content is
copied in RAM
GetFullStatus
(LIN communication ON)
Yes
No
LIN bus OK
B
A
Figure 27: Flow chart power-up of AMIS-30623. 2 cases are illustrated; Case A: LIN lost during operation and Case B: LIN lost at start-up
LIN Lost During Normal Operation
If the LIN communication is lost during normal operation, it is assumed that AMIS-30623 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 also 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 AND FailSafe = 0 there will be no secure positioning. Depending on SleepEn AMIS-30623 will
enter the STOP state or the SLEEP state. See Table 32.
3. If the LIN communication is lost AND FailSafe = 1 there are 2 possibilities:
I. If SecPos[10:0] = 0x400:
no Secure Positioning will be performed
Depending on SleepEn AMIS-30623 will enter the STOP state or the SLEEP state. See Table 32.
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)
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
AMI Semiconductor – June 2006, Rev 3.0
48
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