AMIS-30622 Datasheet, PDF (14/35 Pages) AMI SEMICONDUCTOR – I2C Microstepping Motordriver

AMIS-30622 I²C Microstepping Motordriver
Data Sheet
9.2.1.3 External Switch and HW Pin
Pin SWI and hardwired address pin HW (see § 9.2.4.3
Physical Address) will alternatively attempt to source and
sink a current in/from the external switch (see application
schematic) to test whether it is ON or OFF. This current is
set around 10mA when a 1kΩ external series resistor is
used.
This can be represented by the following time diagram (the
timings are given in § 6).
If the switch is detected ON (closed), then the flag <ESW> is
raised. The status of this flag can be read by the application
via a GetActualPos or a GetFullStatus1 reading
frame. At the falling edge of every current pulse (at around
1kHz), the stepper motor actual position is refreshed
(register ActPos, see § 9.2.2.9), so that the master node
may get synchronous information about the state of the
switch together with the position of the motor. The position
is then given with an accuracy of ± 1 half-step (or micro-
step, depending of the programmed stepping mode). The
block diagram below shows how this function is
implemented for HW.
With the following truth table:
State
Sink
Float
1
Float
1
Float
0
Float
0
HWLo 1
HWLo 1
HWLo 0
HWLo 0
HWHi 1
HWHi 1
HWHi 0
HWHi 0
Source
0
0
1
1
0
0
1
1
0
0
1
1
New State
Float
HWHi
Float
HWLo
HWLo
HWHi
Float
HWLo
Float
HWHi
HWHi
HWLo
HWHi address = "1"
HWLo address = "0"
note that e.g. if HW is connected
to GND, LS-part will report "float"
while HS-part will report "low
resistance detected".
Note
If HW is detected to be floating, motion to the secure position is performed.
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