AMIS-30623 Datasheet, PDF (20/67 Pages) AMI SEMICONDUCTOR – LIN Microstepping Motordriver

AMIS-30623 LIN Microstepping Motordriver
Data Sheet
15.1.4. Hardwired Address HW2
In Figure 11 a simplified schematic diagram is shown of the HW2 comparator circuit.
The HW2 pin is sensed via 2 switches. The DriveHS and DriveLS control lines are alternatively closing the top and bottom switch
connecting HW2 pin with a current to resistor converter. Closing S_TOP (DriveHS = 1) will sense a current to GND. In that case the top
I R convertor output is low, via the closed passing switch S_{PASS_T} this signal is fed to the “R” comparator which output HW2_Cmp is
high. Closing bottom switch S_BOT (DriveLS = 1) will sense a current to VBAT. The corresponding I R converter output is low and via
S_{PASS_B} fed to the comparator. The output HW2_Cmp will be high.
IR
S_{PASS_T}
HW2 _STOP
S_BOT
DriveHS
DriveLS
LOGIC
Debouncer
64 ms
State
High
Low
Float
1
2
3
1 = R2GND
2 = R2VBAT
IR
"R"-Comp
S_{PASS_B}
R_th
COMP
Debouncer
32 µs
HW2_Cmp
3 = OPEN
Figure 11: Simplified Schematic Diagram of the HW2 Comparator
3 cases can be distinguished (see also Figure 11):
- HW2 is connected to ground: R2GND or drawing 1
- HW2 is connected to VBAT: R2VBAT or drawing 2
- HW2 is floating: OPEN or drawing 3
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
AMI Semiconductor – June 2006, Rev 3.0
20
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