8LED2 PMOD

Description

This PMOD provides 8x dual-color LED display output to FPGA designs via two double row PMODs. It is possible to install either type of dual-color LEDs: “common cathode” or “common anode”. The default is “common cathode”, which allows for working with normal logic. WIth normal logic, setting the output “HIGH” lights up the LED. If "common anode" LEDs are installed, JP1 must separate GND, and close the connection to + 3.3V. Common anode uses inverted logic, The LEDs light up when the output is set "LOW".

Schematic

PCB Gerber

8LED2 PMOD Github Repo

Pin Assignments

IceBreaker v1.0

J1#	Label	Description	PMOD1A
1	D1	LED D1 green	4
2	D2	LED D2 green	2
3	D3	LED D3 green	47
4	D4	LED D4 green	45
7	D5	LED D5 green	3
8	D6	LED D6 green	48
9	D7	LED D7 green	46
10	D8	LED D8 green	44

J2#	Label	Description	PMOD1B
1	D1	LED D1 red	43
2	D2	LED D2 red	38
3	D3	LED D3 red	34
4	D4	LED D4 red	31
7	D5	LED D5 red	42
8	D6	LED D6 red	36
9	D7	LED D7 red	32
10	D8	LED D8 red	28

DE0-Nano-SoC

The connection to Intels DE0-Nano-SoC is made through the pmod2nano adapter.

DE0-Nano-SoC

J1#	Label	Description	GPIO0A	GPIO1A
1	D1	LED D1 green	PIN_AF8	PIN_AH27
2	D2	LED D2 green	PIN_AB4	PIN_AH24
3	D3	LED D3 green	PIN_Y4	PIN_AE22
4	D4	LED D4 green	PIN_U11	PIN_AG20
7	D5	LED D5 green	PIN_W12	PIN_AA15
8	D6	LED D6 green	PIN_Y8	PIN_AG26
9	D7	LED D7 green	PIN_W8	PIN_AF23
10	D8	LED D8 green	PIN_Y5	PIN_AF21

J2#	Label	Description	GPIO0B	GPIO1B
1	D1	LED D1 red	PIN_AG6	PIN_AG23
2	D2	LED D2 red	PIN_AE4	PIN_AF18
3	D3	LED D3 red	PIN_T11	PIN_AE20
4	D4	LED D4 red	PIN_AF6	PIN_AD20
7	D5	LED D5 red	PIN_AF4	PIN_AH23
8	D6	LED D6 red	PIN_AF5	PIN_AE19
9	D7	LED D7 red	PIN_T13	PIN_AD19
10	D8	LED D8 red	PIN_AE7	PIN_AE24

Example Code

Verilog

Verilog test program pmod_8led2_1.v (top-level):

// -------------------------------------------------------
// This program tests HW pin assignment, and lights up D1
//--------------------------------------------------------
module pmod_8led2_1 (
  output [0:7] pmodledr
);

  reg led;
  assign pmodledr[7] = led;

  always
  begin
    led = 1'b1;  // light up D1
  end
endmodule

Verilog test program pmod_8led2_2.v (top-level):

// -------------------------------------------------------
// This program is a binary counter, displayed on the pmod
// LED D2-8 green color. The 1Hz clock pulse is on D1 red.
// 12MHz clock: set breakpoint at 23'd5999999 (icebreaker)
// 50MHz clock: set breakpoint at 25'd24999999 (de0-nano)
// -------------------------------------------------------
module pmod_8led2_2 (
  input clk,
  output reg [0:7] pmodledg,
  output reg [0:7] pmodledr
);

  reg clk_1hz = 1'b0;
  reg [22:0] count = 23'd0;
  reg [6:0] lednum = 7'd0;
  assign [1:7] pmodledg = lednum;
  assign [1:7] pmodledr = 7'b0000000;
  assign pmodledr[0] = clk_1hz;

  always @(posedge clk)
  begin
    count   <= count + 1;
    if(count == 23'd5999999)
    begin
      count   <= 0;
      clk_1hz <= ~clk_1hz;
      lednum  <= lednum + 1;
    end
  end
endmodule

VHDL

The Verilog example pmod_8led2_2.v converted to VHDL as pmod_8led2_3.vhd:

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity pmod_8led2_3 is
port ( clk: in STD_LOGIC;
  pmodledg: out STD_LOGIC_VECTOR(0 to 7) := "00000000";
  pmodledr: out STD_LOGIC_VECTOR(0 to 7) := "00000000"
);
end pmod_8led2_3;

architecture arch of pmod_8led2_3 is
  signal clk_1hz: STD_LOGIC := '0';
  signal  lednum: STD_LOGIC_VECTOR(6 downto 0) := "0000000";

  begin
    counter_p: process( clk, clk_1hz, lednum )
    variable count: INTEGER := 0;
    begin
      if( rising_edge(clk) ) then
        count := count + 1;
        if( count = 24999999 ) then
           count := 0;
           clk_1hz <= NOT clk_1hz;
         lednum  <= std_logic_vector( unsigned(lednum) + 1);
        end if;
       end if;

    pmodledr(0) <= clk_1hz;
    pmodledg(1) <= lednum(6);
    pmodledg(2) <= lednum(5);
    pmodledg(3) <= lednum(4);
    pmodledg(4) <= lednum(3);
    pmodledg(5) <= lednum(2);
    pmodledg(6) <= lednum(1);
    pmodledg(7) <= lednum(0);
  end process counter_p;
end arch;

8LED2 PMOD, connected to a DE0-Nano-SoC board