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Revision as of 23:29, 10 March 2007 (view source) Hansbe (Talk | contribs) m ← Older edit		Revision as of 12:02, 19 May 2008 (view source) Yngveha (Talk | contribs) (→VHDL Programmeringstips) Newer edit →
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	wait until (CLK='1' and CLK'stable(2 ns));		wait until (CLK='1' and CLK'stable(2 ns));
		+
		+
		+	== array/vektorer, forskjellen på '''downto''' og '''to''' ==
		+
		+	testbenkkode:
		+
		+	STIMULI : process
		+
		+	begin
		+	downs <= x"05";
		+	wait for 5 ns;
		+	ups <= downs;  -- ups = 0x05
		+	wait for 5 ns;
		+	downs <= x"03";
		+	wait for 5 ns;
		+	--ups(ups'range) <= downs(downs'reverse_range); -- ikke lovlig syntax
		+
		+	ups(4 to 7) <= downs(3 downto 0); -- ups = 0x04
		+	wait for 5 ns;
		+	downs <= x"E4";
		+	wait for 5 ns;
		+	ups <= "0000" & downs(3 downto 0); -- ups = 0x04
		+	wait for 5 ns;
		+	downs <= "1111" & ups(4 to 7); -- downs = 0xF4;
		+	wait;
		+	end process;

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Revision as of 12:02, 19 May 2008

Contents 1 VHDL Programmeringstips 1.1 Hvordan teste om alle bit i en std_logic_vector = '1' 1.2 Hvordan sette alle bit i en std_logic_vector like 1.3 Hvordan vente på en verdi som skal være stabil en periode 1.4 array/vektorer, forskjellen på downto og to

VHDL Programmeringstips

Hvordan teste om alle bit i en std_logic_vector = '1'

if A = (A'range => '1') then
   ...
else
   ...
end if;

Hvordan sette alle bit i en std_logic_vector like

A <= (others => '1');
 
A_2D <= (others=>(others => '1'));    --hvis todimensjonalt array

Hvordan vente på en verdi som skal være stabil en periode

wait until (CLK='1' and CLK'stable(2 ns));

array/vektorer, forskjellen på downto og to

testbenkkode:

STIMULI : process

 begin
downs <= x"05";
wait for 5 ns;
ups <= downs;  -- ups = 0x05
wait for 5 ns;
downs <= x"03";  
 wait for 5 ns;
--ups(ups'range) <= downs(downs'reverse_range); -- ikke lovlig syntax

ups(4 to 7) <= downs(3 downto 0); -- ups = 0x04
 wait for 5 ns; 
 downs <= x"E4";   
 wait for 5 ns;
 ups <= "0000" & downs(3 downto 0); -- ups = 0x04
 wait for 5 ns;
 downs <= "1111" & ups(4 to 7); -- downs = 0xF4;
wait;
 end process;