I need to make an output pulse (within certain conditions) becomes a '1'
constant (in an LED).
I was able to code, but the output is stuck at VCC. I do not know how to
fix this. Can anyone help me please?
Code:
ARCHITECTURE behavioral OF check_minutes IS
SIGNAL aux: STD_LOGIC := '0';
BEGIN
accept_minutes: PROCESS(enable,data) --processo de aceitar ou não a
temperatura inserida.
BEGIN
IF(data>="000001" AND data<="111011" AND enable='1') THEN
aux <= '1';
END IF;
END PROCESS accept_minutes;
minled <= aux;
END ARCHITECTURE behavioral;
Attached files:
-
simula__o.png
3.7 KB -
c_digo.png
7.2 KB
You have to set "aux <= '0' in an else-tree. This one generates a latch.
thank u for ur reply, pat. It really works, but I want to make a CONSTANT '1'. Can u help me with that? what u say generates one pulse. I want one constant 1 after this pulse.
> I want one constant 1 after this pulse.
In this case you need a condition to reset 'aux' to '0' at the time you
want. For example when 'enable = 0' or any other signal.
By the way: Such combinatorical logic generates latches! Only for
simulation is it ok, but in real hardware is it very problematic. The
better way is to use a register. But this needs a proces with a clock.
Attached files:
-
case_1.png
11 KB -
case_2.png
10 KB
I'm sending prints of cases, both code and simulation. It's in attach. In second case the constant 1 works, but before the constant 1, it's unknown, as u can see. do u know how do I transform this unknown to '0'?
Paulo Henrique Silva wrote: > In second case the constant 1 works, but before the constant 1, it's > unknown, as u can see. do u know how do I transform this unknown to '0'? Your shown code describes how you assign the signal "aux". It has an initialization to zero. If your simulator takes the init-value into account, aux should never be undefined. If your simulator ignores the init-value, then aux should at least be well defined once enable gets high. But your simulation result does not show the signal "aux" but a signal "minled" which does not at all appear in your code. Maybe you show us, how minled depends on aux. There one should the answer to your question. By the way: as you have a clock (according to your simulation) you really should follow the recommendation of Pat a Mat and work with registers instead of latches. That will give you much less trouble.
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