02-22-2019, 03:22 PM
After trying to get the switches (DIP and pushbutton) Alchitry Io working for a little too long it finally occurred to me that pulldowns need to be enabled for each of the pins attached to a switch. If pulldowns are not enabled the pin will typically float high. The pulldown resistor can be enabled on a pin by pin basis in the constraints file as follows:
Code:
set_property PACKAGE_PIN C4 [get_ports {dip_sw[0]}]
set_property IOSTANDARD LVCMOS33 [get_ports {dip_sw[0]}]
set_property PULLDOWN TRUE [get_ports {dip_sw[0]}]