PD-1141 Hardware Manual (Rev. 1.04 / 2013-JUL-23)
12
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3.3.2.1
Digital Inputs IN_1, IN_2, IN_3
The eight pin connector of the PD-1141 provides three multi-purpose digital inputs IN_1, IN_2 and IN_3.
All three inputs accept up-to +24
V input signals. They are protected against these higher voltages using
voltage resistor dividers together with limiting diodes against voltages below 0
V (GND) and above +3.3
V
DC (see figure below).
+3.3V
IN_0
IN_1
IN_2
microcontroller (all)
and TMC429 (IN_0, IN_1)
10k
22k
1nf
GND
GND
GND
common switch for all
three digital inputs
1k
+5V
Figure 3.5 General purpose inputs (simplified input circuit)
Refer to the PD-1141 TMCL Firmware Manual (SIO command) for further information about switching the
pull-up resistors for all digital inputs on / off.
The three digital inputs have alternate functionality depending on configuration in software. The
following functions are available:
Label
(pin)
Default function
Alternate function 1
Alternate function 2
IN_0 (6)
General purpose
digital input
STOP_L - left stop switch input
connected to processor and
TMC429 REF input (supporting
left
stop
functionality
in
hardware)
IN_0 (6)
IN_1 (7)
General purpose
digital input
STOP_R - right stop switch input
connected to processor and
TMC429 REF input (supporting
right stop switch functionality in
hardware)
IN_1 (7)
IN_2 (8)
General purpose
digital input
HOME - home switch input
(connected to processor)
IN_2 (8)
Table 3.7 Multipurpose inputs / alternate functions
All three digital inputs are connected to the on-board processor and can be used as general purpose
digital inputs (default).
