18 |
M 5 7 5 1
5.3.3 Discrete Input/Output (DIO)
The Layer N SP-013 features 2 configurable discrete I/O pins. These can be used for a myriad of applications
including driving relays, physical alarms, or sensing dry contacts like door switches. The user may configure
the polarity of the inputs (active
HIGH
or active
LOW
) or
Disable
the DIO to utilize the outputs (ON/OFF,
PWM, SERVO).
The Discrete I/O input shares the output circuitry. The internal process drives the output control signal to
turn on the output driver which will force the output low. When the state of the DIO input signal is to be
read the processor applies 3.3 V
DC
to the Input Bias signal and reads the level detected at the Input Sense. If
the output is inactive an external signal may be used to force the input level low. A diode protects external
positive voltages, allowing the output driver to activate loads greater than the internal 3.3 V
DC
.
Figure 19: SYNC interface discrete I/O input configuration
Figure 20: Digital/Discrete I/O circuitry
