ThingMagic Astra-EX - Manual (Page 40)

Using GPIO
M6 and Astra-EX User Guide 40
Using GPIO
The M6 and Astra-EX Reader includes a 15-pin D-Sub connector (also commonly
referred to as a VGA connector). This connector is used to support four opto-isolated
general purpose inputs and four opto-isolated general purpose outputs. The values of the
GPIO lines can be Get and Set using the MercuryAPI. See the respective guide for more
details on software control of these signals. For ease of testing the following parts
(included in M6 and Astra-EX devkit) can be used to provide a terminal block interface to
the GPIO pins:
– VGA male to male connector (for GPIO) [L-Com Part# DMB520M]
– VGA to terminal block (for GPIO) [L-Com Part# DGBH15FT]
Inputs
The four opto-isolated inputs support the following input levels:
V-low (Logic 0) = 0-0.8V
V-high (Logic 1) = 3-30V
5mA max current with 24V input
It is recommended that external devices guarantee a minimum pulse width of at least
100ms.
Outputs
The four opto-isolated outputs support power sourcing, up to +30V with current sink up to
200mA, through an external power supply connected between V-GPO and ISO-GND
(pins 5 and 6).
Using the MercuryAPI the output signals (see note under Connector Pinout for
enumeration values) can be set as follows:
gpoSet(GPIO_#, 0) sets pin corresponding to GPIO enumeration to Vhigh through
10kohm pull up resistor to V-GPO.
gpoSet(GPIO_#, 1) sets pin corresponding to GPIO enumeration to Vlow through
effective short (through isolated FET switch) to ISO-GND.
All outputs have an active pull down to ISO-GND.