AMIS-30623 LIN Microstepping Motordriver
Data Sheet
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
OPEN
R2VBAT
R2GND
R2VBAT
t
t
Tsw = 1024 µs
DriveHS
DriveLS
Tsw_on = 128 µs
t
"R"-Comp
Rth
t
t
HW2_Cmp
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 SBOT is closed a current is sensed, the output of the I ꢀ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
state and the new state will be High. (see also Table 16). The next time SBOT is closed the same conditions are observed. The previous
state was High, so based on Table 16 the new state remains unchanged. This high state will be interpreted as HW2 address = 1
OPEN
In case the HW2 connection is lost (broken wire, bad contact in connector) the next time SBOT is closed this will be sensed. There will be
no current, the output of the corresponding I ꢀR converter is High and the HW2_Cmp will be low. The previous state was High. Based
in Table 16 one can see that the state changes to float. This will trigger a motion to secure position after a debounce time of 64 ms.
This prevents false triggering in case of false micro interruptions of the power supply. See also Electrical transient conduction along
supply lines
R2GND
If a resistor is connected between HW2 and the GND, a current is sensed every 1024 µs whet STOP is closed. The output of the top I ꢀ
R converter is low and as a result the HW2_Cmp output switches to High. Again based on the stated diagram in Table 1 one can see
that the state will change to Low. This low state will be interpreted as HW2 address = 0.
AMI Semiconductor – June 2006, Rev 3.0
21
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