AMIS-30623 Datasheet, PDF (19/65 Pages) AMI SEMICONDUCTOR – LIN Microstepping Motordriver

AMIS-30623
Table 16: State Diagram of the HW2 Comparator
Previous State
DriveLS DriveHS
Float
1
0
Float
1
0
Float
0
1
Float
0
1
Low
1
0
Low
1
0
Low
0
1
Low
0
1
High
1
0
High
1
0
High
0
1
High
0
1
HW2_Cmp
0
1
0
1
0
1
0
1
0
1
0
1
New State
Float
High
Float
Low
Low
High
Float
Low
Float
High
High
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
The logic is controlling the correct sequence in closing the switches and in interpreting the 32 μs 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 16 the state is depending on the previous state, the condition of the 2 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
DriveHS
R2VBAT
Tsw = 1024 μs
OPEN
R2VBAT
R2GND
t
t
DriveLS
Tsw_on = 128 μs
t
"R"-Comp
R_th
t
HW2_Cmp
t
State
t
Figure 12: Timing Diagram Showing the Change in States for HW2 Comparator
R2VBAT
A resistor is connected between VBAT and HW2. Every 1024 μs S_BOT is closed a current is sensed, the output of the I Æ R converter is
low and the HW2_Cmp output is high. Assuming the previous state was floating, the internal LOGIC will interpret this as a change of
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