Honored ContributorI'm working on a input string, and need to set around 100 bits as input, however, I don't know how to set a input with a fixed pattern, say, "11101001110000......." as input. So, where should set for this purpose?
Thanks!
Honored Contributorin what? a testbench in simulation? on a pin of a physical chip? and ethernet interface?
Please be more specific.Honored ContributorThe purpose is TI generate patterns for simple test. And I use MAXII micro board. So, I have to define input logic of shift register for serial output.
Honored Contributorso, just to be clear, you are using the MAX2 to generate the test pattern for something else, you're not testing the max2?
Honored ContributorYes, you are right.
Thanks.Honored ContributorAnyone can help me?
Honored ContributorAll you need is a shift register that powers up to an initial value and then pumps it out.
Honored ContributorTricky, thanks for the reply.
You mean to connect the inputs of shift registers to either bcc or gnd directly? If it's true, how can I change the input patterns other time cycles?Honored ContributorYou will need a simple bit generator based on cyclic shift register as Tricky suggested:
-- not tested
process(reset,clk)
begin
if reset = '1' then
shift_reg <= x"0123456789ABCDEF"; -- 64 bits initial value
elsif rising_edge(clk) then
shift_reg <= shift_reg(62 downto 0) & shift_reg(63);
end if;
end process;Thanks, Kaz.
It's the behavior of shift register. I need a 16 bit width. After assigned the initial value and 16 clk cycle passed, I will need another 16 bits input. How to generate the subsequent 16 bits and the following ones? Thanks! CliffHonored ContributorIf I understood you, you need to design a 16 bit shift register as above replacing 64 bits with 16 bits then kick it on every clock edge.
For changing value every 16 clock cycles then simply load new value into shift register. You will need a small counter say 0 ~ 3 to load a specific value at each count. if count 0 load x"...", else if count 1 load x"...." and so on.
