ThingMagic Sargas User Guide
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If the 5 V internal source is used with internal 10KOhm resistors, (5V-OUT connected to V-GPO),
ISO-GND must be connected to SYS-GND. If an external voltage source is used at V-GPO in
place of the internal 5V source, make sure its negative side is connected to ISO-GND. If an
external voltage is used with an external resistor, make sure its negative side is connected to ISO-
GND and connect V-GPO to ISO-GND (to prevent the output lines from driving each other
through a floating V-GPO pin).
2) gpoSet(GPIO_#, 0) sets the pin corresponding to the GPIO enumeration to Vlow by “shorting”
the output level to ISO-GND
.
Note
For non -isolated applications connect grounds together (pin 7 and 8) and V -GPO to 5V
(pins 2 and 1). With this configuration the reader provides the +5V supply and can sink up to
200mA, total.
For convenience, the schematic diagram of the GPIO circuits of the Sargas reader are shown in
Figure
19
so you can more easily determine the external connections that will work for your application.
9.4.1
Figure 19: Schematic Diagram of GPIO Circuitry
