AMIS-30621 LIN Micro-stepping Motor Driver
Data Sheet
Table 15: State Diagram of the HW2 Comparator
Previous State
Float
Float
Float
Float
Low
Low
Low
Low
High
DriveLS
DriveHS
HW2_Cmp
New State
Float
High
Float
Low
Condition
R2GND or OPEN
R2VBAT
R2VBAT or OPEN
R2GND
R2GND or OPEN
R2VBAT
R2VBAT or OPEN
R2GND
R2GND or OPEN
R2VBAT
R2VBAT or OPEN
R2GND
Drawing
1 or 3
2
2 or 3
1
1 or 3
2
2 or 3
1
1 or 3
2
2 or 3
1
1
1
0
0
1
1
0
0
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
Low
High
Float
Low
Float
High
High
Low
High
High
High
The logic is controlling the correct sequence in closing the switches and in interpreting the 32μs debounced HW2_Cmp output
accordingly. The output of this small state-machine is corresponding to:
• High or address = 1
• Low or address = 0
• Floating
As illustrated in Table 17 the state is depending on the previous state, the condition of the two switch controls (DriveLS and DriveHS)
and the output of HW2_Cmp. Figure 12 is showing an example of a practical case where a connection to VBAT is interrupted.
Condition
OPEN
R2VBAT
R2GND
R2VBAT
t
t
Tsw = 1024 μs
DriveHS
DriveLS
Tsw_on = 64 μs
t
"R"-Comp
Rth
t
t
HW2_Cmp
State
t
Figure 12: Timing Diagram Showing the Change in States for HW2 Comparator
AMI Semiconductor – Sept. 2007, Rev 1.5
19
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