...
The XD235 and XD1035 have a 12-pin GPIO switch and an LED connector, which allows the player to control external LEDs or other devices. The port can supply 3.3V@300mA to PWR pins and sink or source 24mA on each button pin. Auxiliary power is 1A.
The GPIO port is a standard design manufactured by Phoenix Contact, Wurth Electronics, and others. Pluggable GPIO terminal blocks can be inserted into the GPIO connector to make bare-wire contacts (see here for an example part). These terminal blocks can be purchased from the BrightSign Store. If you wish to source your own terminal blocks, make sure to use 4-pin or 6-pin blocks (12-pin blocks are extremely difficult to remove from the GPIO port).
Connect the LED outputs to the LED ANODE and connect the LED CATHODE to the ground. If you want to connect another device, then the output is capable of sourcing or sinking up to 3.3V at 24mA, but there is a series resistor of 100Ω in each line.
The GPIO also allows for connecting of external contact closures to the ground. In order to connect a switch, connect one side of the switch to the switch input, and connect the other side to one of the ground pins on the GPIO connector.
If one BrightSign player is driving the inputs on another BrightSign player, then you can drive at most three inputs from one output. The following calculations explain this limitation:
The GPIO outputs have 100Ω series resistors; the GPIO inputs have 1K pullup resistors to 3.3V; and the input threshold is 2V high and .8V low. The high voltage is not problematic, but the low voltage can be if there are too many inputs connected to one output.
1 out driving 1 in | V=3.3*100/(100+1,000)=0.3 |
1 out driving 2 in | V=3.3*100/(100+500)=0.55 |
1 out driving 3 in | V=3.3*100/(100+333.3)=0.76 |
1 out driving 4 in | V=3.3*100/(100+250)=.94 (This is too high, so 1 output driving 3 inputs is the maximum) |
GPIO Pinout
The following table illustrates the pinout of the GPIO on the XD235 and XD1035:
Pin | Function | Pin | Function |
|---|---|---|---|
1 | GND | 7 | GND |
2 | 3.3V | 8 | 3.3V |
3 | BUTTON 0 | 9 | BUTTON 4 |
4 | BUTTON 1 | 10 | BUTTON 5 |
5 | BUTTON 2 | 11 | BUTTON 6 |
6 | BUTTON 3 | 12 | BUTTON 7 |
The following schematic illustrates the pinout of the GPIO connector:
...
WiFi Antenna Connectors
The XD235 and XD1035 have two SMA connectors to allow easy installation of external WiFi antennas.
...