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 STOP (DriveHS = 1) will sense a current to GND. In that case the top
IꢀR convertor output is low, via the closed passing switch SPASS_T this signal is fed to the “R” comparator which output HW2_Cmp is
high. Closing bottom switch SBOT (DriveLS = 1) will sense a current to VBAT. The corresponding IꢀR converter output is low and via
SPASS_B fed to the comparator. The output HW2_Cmp will be high.
SPASS_T
IꢁR
State
DriveHS
HW2
High
Low
STOP
LOGIC
Debouncer
64 ms
Float
SBOT
DriveLS
"R"-Comp
1
2
3
IꢁR
SPASS_B
Rth
COMP
Debouncer
1 = R2GND
2 = R2VBAT
3 = OPEN
32 µs
HW2_Cmp
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
Float
Float
Float
Float
Low
DriveLS DriveHS
HW2_Cmp
New State Condition
Drawing
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
Float
High
Float
Low
R2GND or OPEN
R2VBAT
R2VBAT or OPEN
R2GND
1 or 3
2
2 or 3
1
1 or 3
2
2 or 3
1
1 or 3
2
2 or 3
1
Low
R2GND or OPEN
R2VBAT
R2VBAT or OPEN
R2GND
Low
Low
Low
High
High
High
High
High
Float
Low
Float
High
High
Low
R2GND or OPEN
R2VBAT
R2VBAT or OPEN
R2GND
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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