Basys 3, working, but LED digits are flickering

[Fancellu]

Just some silly hello world code (I'm a super newbie to FPGAs)

 

Vivado 2017.4, windows 7

 

xdc as per https://reference.digilentinc.com/learn/programmable-logic/doc/github/digilent-xdc =>

set_property IOSTANDARD LVCMOS33 [get_ports a]
set_property IOSTANDARD LVCMOS33 [get_ports b]
set_property IOSTANDARD LVCMOS33 [get_ports c]
set_property PACKAGE_PIN U16 [get_ports c]
set_property PACKAGE_PIN W19 [get_ports a]
set_property PACKAGE_PIN T17 [get_ports b]

vhdl=>

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity AND_GATE is
    Port ( a : in STD_LOGIC;
           b : in STD_LOGIC;
           c : out STD_LOGIC);
end AND_GATE;

architecture Behavioral of AND_GATE is

begin

    c<= a AND b;

end Behavioral;

=============

Now, it runs just fine, but for some reason my Basys 3's LED 4 digit display is flickering like crazy, with a faint 8888. Is this a known issue? Am I missing something?
 

Thanks

 

[Fancellu]

Aha, open implemented design, settings, bitstream, configure additional bitstream settings, configuration, scroll down, unused IOB_PINS

Pullup no good, as all my leds go on, however at least does turn off 7 segment.

Pullnone seems to have fixed it, hurrah.

Would really be nice if they added this to the basys 3 data sheet.



 

[jpeyron]

Hi @Fancellu,

I ran your VHDL code on the Basys 3 using Vivado 2017.4 on window 7 and got the same results. Here is a forum thread that discusses this issue and a solution.

cheers,

JOn

[jpeyron]

Hi @Fancellu,

I am sorry about the inconvenience, I have passed this on to our content team.

cheers,

Jon