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Altera_Forum's avatar
Altera_Forum
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14 years ago

multiple driver error during simulation

Hi I am doing a project and am stuck in the synthesis part in Quartus. The code was successfully compiled using icarus verilog software.But while compiling the code in Quartus , I get some error...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

Your flag is driven in two processes. the second process sets it permanently to high...

You must have a clock input as fast as serial stream (at least) then you run a counter(integer 0 ~ 8) set at zero at MSB or LSB location then increment to 8 and reset zero. 


(vhdl clocked process)
--detect edge of switch
switch_d <= switch;
if switch = '1' and switch_d = '0' then
   count <= 1;
elsif count < 8 then
   count <= count + 1;
end if;
if count < 8 then
    output(count) <= input;
end if;
if count = 7 then
    valid <= '1';
else
    valid <= '0';
end if;