Basic I/O; Tri-Color Leds - Xilinx Arty A7 Reference Manual

22.8.2018
The CK_RST signal (see the Arty A7 Schematic) is also connected to the FT2232HQ device via JP2. When JP2 is shorted, the
FT2232HQ can trigger a Microblaze reset, mimicking the behavior of Arduino and chipKIT boards when sketches are loaded. Note the
CK_RST signal is also connected to the red RESET button and the RST pin of J7 on the shield connector (these connections are not
shown in the figure below).
The connections between the FT2232HQ and the Artix-7 are shown in Figure 6.
(https://reference.digilentinc.com/_detail/arty/arty_uart.png?id=reference%3Aprogrammable-logic%3Aarty-a7%3Areference-manual)
Figure 8.1 Arty A7 UART

9 Basic I/O

The Arty A7 includes four tri-color LEDs, 4 switches, 4 push buttons, 4 individual LEDs, and a reset button, as shown in Figure 16. The
push buttons and slide switches are connected to the FPGA via series resistors to prevent damage from inadvertent short circuits (a short
circuit could occur if an FPGA pin assigned to a push button or slide switch was inadvertently defined as an output). The four push
buttons are "momentary" switches that normally generate a low output when they are at rest, and a high output only when they are
pressed. Slide switches generate constant high or low inputs depending on their position.
The red reset button labeled "RESET" generates a high output when at rest and a low output when pressed. The RESET button is
intended to be used in Microblaze designs to reset the processor, but you can also use it as a general purpose push button. Note that it is
also tied to the RST pin on J7 of the shield connector and to the FT2232 UART device via JP2, though these connections are not shown
in the figure below.
(https://reference.digilentinc.com/_detail/arty/arty_gpio.png?id=reference%3Aprogrammable-logic%3Aarty-a7%3Areference-manual)
Figure 9.1 Arty A7 GPIO ()
The four individual high-efficiency LEDs are anode-connected to the FPGA via 330-ohm resistors, so they will turn on when a logic
high voltage is applied to their respective I/O pin. Additional LEDs that are not user-accessible indicate power-on, FPGA programming
status, and USB and Ethernet port status.

9.1 Tri-Color LEDs

The Arty A7 contains four tri-color LEDs. Each tri-color LED () has three input signals that drive the cathodes of three smaller internal
LEDs: one red, one blue, and one green. Driving the signal corresponding to one of these colors high will illuminate the internal LED ().
The input signals are driven by the FPGA through a transistor, which inverts the signals. Therefore, to light up the tri-color LED (), the
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