AMIS-30624 Datasheet, PDF (19/56 Pages) AMI SEMICONDUCTOR – I2C Microstepping Motordriver

AMIS-30624
Three cases can be distinguished (see also Figure 10):
- HW is connected to ground: R2GND or Drawing 1
- HW is connected to VBAT: R2VBAT or Drawing 2
- HW is floating: OPEN or Drawing 3
Table 15: State Diagram of the HW Comparator
Previous State DriveLS DriveHS HW_Cmp
Float
1
0
0
Float
1
0
1
Float
0
1
0
Float
0
1
1
Low
1
0
0
Low
1
0
1
Low
0
1
0
Low
0
1
1
High
1
0
0
High
1
0
1
High
0
1
0
High
0
1
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 32μs de-bounced HW_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 15, the state is depending on the previous state, the condition of the two switch controls (DriveLS and DriveHS)
and the output of HW_Cmp. Figure 11 shows an example of a practical case where a connection to VBAT is interrupted.
Condition
DriveHS
R2VBAT
Tsw = 1024 μs
DriveLS
Tsw_on = 128 μs
OPEN
R2VBAT
R2GND
t
t
t
"R"-Comp
R_th
t
HW_Cmp
t
State
PC20060926.2
t
Figure 11: Timing Diagram Showing the Change in States for HW Comparator
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