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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.
t
R
th
Tsw = 1024
μ
s
DriveHS
"R"-Comp
t
t
t
DriveLS
HW2_Cmp
State
t
Tsw_on = 128
μ
s
Condition
R2VBAT
OPEN
H
L
F
H
H
H
H
R2VBAT
R2GND
F
H
F
F
H
H
L
L
t
Figure 12: Timing Diagram Showing the Change in States for HW2 Comparator
R2VBAT
A resistor is connected between VBAT and HW2. Every 1024
μ
s S
BOT
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 S
BOT
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 S
BOT
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 1
6 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
μ
s whet S
TOP
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.
21
AMI Semiconductor
– June 2006, Rev 3.0
www.amis.com