Ho! No FPGA-reset button on armadeus card.
From ArmadeusWiki
That is a constant comment about the armadeus apf9328 card. Most of FPGA designer learn that it's mandatory to use a reset in each module with structure like it:
myprocess : process (clk,reset)
begin
if reset = '1' then
-- init values
elsif rising_edge(clk) then
-- processing code
end if;
end process myprocess;
But by default there is no reset button on card, then what to do ?
Plug a reset button
Of course it's possible to solder a reset button on card, there are a large amount of I/O on connector and one can serve to do it.
Generate the reset internal
But it is possible to use initial state of fpga after configuration with this code:
---------------------------------------------------------------------------
Entity clock_and_reset_gen is
---------------------------------------------------------------------------
generic(
invert_reset : std_logic := '0' -- 0 : not invert, 1 invert
);
port
(
-- external signals
ext_clk : in std_logic ;
--internal generated signals
gls_clk : out std_logic ;
gls_reset : out std_logic
);
end entity;
---------------------------------------------------------------------------
Architecture clock_and_reset_gen_1 of clock_and_reset_gen is
---------------------------------------------------------------------------
signal dly: std_logic := '0';
signal rst: std_logic := '0';
signal int_reset : std_logic;
begin
int_reset <= '0';
----------------------------------------------------------------------------
-- RESET signal generator.
----------------------------------------------------------------------------
process(ext_clk)
begin
if(rising_edge(ext_clk)) then
dly <= ( not(int_reset) and dly and not(rst) )
or ( not(int_reset) and not(dly) and rst );
rst <= ( not(int_reset) and not(dly) and not(rst) );
end if;
end process;
gls_clk <= ext_clk;
gls_reset <= rst xor invert_reset ;
end architecture clock_and_reset_gen_1;