User manual
22.8.2018 Cora Z7 Reference Manual [Reference.Digilentinc]
https://reference.digilentinc.com/reference/programmable-logic/cora-z7/reference-manual 15/20
The Cora Z7 board includes two tri-color LEDs and 2 push buttons as shown in Figure 11.1. The push buttons are connected to the
Zynq PL via series resistors to prevent damage from inadvertent short circuits (a short circuit could occur if an FPGA pin assigned to a
push button was inadvertently defined as an output). The two 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.
(https://reference.digilentinc.com/_media/reference/programmable-logic/cora-z7/cora-basic-io.png)
Figure 11.1. Cora Z7 Basic I/O
The Cora Z7 board contains two 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 Zynq PL through a transistor, which inverts the signals. Therefore, to light up the tri-color
LED (), the corresponding signals need to be driven high. The tri-color LED () will emit a color dependent on the combination of
internal LEDs that are currently being illuminated. For example, if the red and blue signals are driven high and green is driven low, the
tri-color LED () will emit a purple color.
Digilent strongly recommends the use of pulse-width modulation (PWM) when driving the tri-color LEDs. Driving any of the inputs to a
steady logic ‘1’ will result in the LED () being illuminated at an uncomfortably bright level. This can be avoided by ensuring that none of
the tri-color signals are driven with more than a 50% duty cycle. Using PWM also greatly expands the potential color palette of the tri-
color led. Individually adjusting the duty cycle of each color between 50% and 0% causes the different colors to be illuminated at
different intensities, allowing virtually any color to be displayed.
Pmod connectors are 2×6, right-angle, 100-mil spaced female connectors that mate with standard 2×6 pin headers. Each 12-pin Pmod
connector provides two 3.3V VCC () signals (pins 6 and 12), two Ground signals (pins 5 and 11), and eight logic signals, as shown in
Figure 15.1. The VCC () and Ground pins can deliver up to 100mA of current, but care must be taken not to exceed any of the power
budgets of the onboard regulators or the external power supply (see the 3.3V rail current limits listed in the “Power Supplies” section).
(https://reference.digilentinc.com/_detail/reference/programmable-logic/arty-z7/arty-z7-pmod.png?id=reference%3Aprogrammable-logic%3Acora-
z7%3Areference-manual) Figure 12.1. Pmod Port Diagram
Digilent produces a large collection of Pmod accessory boards that can attach to the Pmod expansion connectors to add ready-made
functions like A/D’s, D/A’s, motor drivers, sensors, and other functions. See www.digilentinc.com (http://www.digilentinc.com) for
more information.
Each Pmod connector found on Digilent FPGA boards falls into one of four categories: standard, MIO connected, XADC, or high-
speed. The Cora Z7 has two Pmod connectors, both of which are of the high-speed type. The following section describes the high-speed
type of Pmod connector.
11 Basic I/O
11.1 Tri-Color LEDs
12 Pmod Connectors
12.1 High-Speed Pmods
