AMIS-30624_13 Datasheet, PDF (20/52 Pages) ON Semiconductor – I2C Micro-stepping Motor Driver

Condition
DriveLS
R2 VBAT
Tsw = 1024 ms
AMIS−30624, NCV70624
OPEN
R2 VBAT
DriveHS
Tsw_on = 128 ms
R2 GND
t
t
t
“R”−Comp
R_th
t
HW_Cmp
t
State
t
Figure 11. Timing Diagram Showing the Change in States for HW Comparator
R2VBAT
A resistor is connected between VBAT and HW. Every
1024 ms S_BOT is closed and a current is sensed. The output
of the I  R converter is low and the HW_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 15). The next time S_BOT is closed
the same conditions are observed. The previous state was
high so based on Table 15 the new state remains unchanged.
This high state will be interpreted as HW address = 1.
OPEN
In case the HW 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 HW_Cmp
will be low. The previous state was high. Based in Table 15
one can see that the state changes to float. This will trigger
a motion to secure position after a debounce time of 64 ms,
which prevents false triggering in case of micro−
interruptions of the power supply.
R2GND
If a resistor is connected between HW and the GND, a
current is sensed every 1024 ms when S_TOP is closed. The
output of the top I  R converter is low and as a result the
HW_Cmp output switches to high. Again based on the stated
diagram in Table 15 one can see that the state will change to
Low. This low state will be interpreted as HW address = 0.
External Switch SWI
As illustrated in Figure 12 the SWI comparator is almost
identical to HW. The major difference is in the limited
number of states. Only open or closed is recognized leading
to respectively ESW = 0 and ESW = 1.
http://onsemi.com
20