AMIS-30621 LIN Micro-stepping Motor Driver
Data Sheet
+20000
+10000
ActPos = +30000
0
Motion direction
TagPos = -30000
-10000
-20000
Figure 10: Motion Direction is Function on Difference Between ActPos and TagPos
14.1.4. Hardwired Address HW2
Figure 11 shows a simplified schematic diagram of the HW2 comparator circuit. The HW2 pin is sensed via two 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 IÆ R converter 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 IÆ R converter output is low and via SPASS_B fed to the comparator. The output HW2_Cmp will be
high.
SPASS_T
IÎR
State
DriveHS
HW2
High
Low
STOP
LOGIC
Float
SBOT
DriveLS
"R"-Comp
1
2
3
IÎR
SPASS_B
Rth
COMP
32 μs Debouncer
1 = R2GND
2 = R2VBAT
3 = OPEN
HW2_Cmp
Figure 11: Simplified Schematic Diagram of the HW2 Comparator
Three cases can be distinguished (see Figure 11):
• HW2 is connected to ground: R2GND of drawing 1
• HW2 is connected to VBAT: R2VBAT or drawing 2
• HW2 is floating: OPEN or drawing 3
AMI Semiconductor – Sept. 2007, Rev 1.5
18
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