UP-DOWN COUNTER
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity updowncount is
port(reset,c,clk:in std_logic;
s:inout std_logic_vector(3 downto 0));
end updowncount;
architecture Behavioral of updowncount is
begin
process(reset,c,clk,s)
begin
if reset='1' then
s<="0000";
elsif c='1' and rising_edge(clk) then
s<=s+1;
elsif c='0' and rising_edge(clk) then
s<=s-1;
end if;
end process;
end Behavioral;UP-DOWN COUNTER
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity updowncount is
port(reset,c,clk:in std_logic;
s:inout std_logic_vector(3 downto 0));
end updowncount;
architecture Behavioral of updowncount is
begin
process(reset,c,clk,s)
begin
if reset='1' then
s<="0000";
elsif c='1' and rising_edge(clk) then
s<=s+1;
elsif c='0' and rising_edge(clk) then
s<=s-1;
end if;
end process;
end Behavioral;
library ieee;
library ieee; use ieee.std_logic_1164.all; entity 3bitrc is port(
These are predefined words in VHDL standards. Bit indicates that the data type is a bit i. e. 0 or 1. A bit_vector is an array of bits. example: a: in bit; b: in bit_vector(1 downto 0);
In VHDL, std_logic is a data type. It is assigned to input and / or output variables. It means that the variable is a standard logic type i. e. a logic bit which accepts or provides one bit data, either 1 or 0.
vhdl is a hardware definition languega to be run on a dsp. it describes circuits, a logical hardware structure. a rake receiver is a piece of hardware that enables every WCDMA-receiver (e i a mobile working with the umts standard) to handel a cdma-coded bit sequence. i know... cant describe it in an easier way.... ;)
it has for bit or states for its output
it has for bit or states for its output
There are five flip-flops in a five-bit ripple counter.
watchdog timer is a 16 bit counter that resets the processor when it rolls over to zero. The processor can reset the counter or turn it off, but, correctly used, it will reset the processor in case of a code crash
a 2 bit counter is a counter which have only 2 bits i.e. the posibble counting states are 00, 01, 10,11,00. It may also be known as MOD 3 counter. It can be realized by using 2 Flip flop.
designed a sequential circuit that will function as 2 bit-up down counter
binary coded decimal counter with carry propagated bit to bit by ripple method instead of carry lookahead combinatorial logic method. this is easy to build but has long settling time with invalid codes occurring before it settles. for example these counters will generate a 1010 code between 1001 and 0000.