since both edges are used, therefore output will be delayed by - half cycle. all entity manchester_code2 is port ( clk, din : in std_logic dout : out std_logic ) end entity architecture arch of manchester_code2 is signal dout_reg, dout_next : std_logic begin process ( clk ) begin - both rising and falling edge are used as manchester_code uses - both edges of the clock to generate output. manchester_code2.vhd library ieee use ieee.std_logic_1164. ![]() all entity edgeDetector is port ( clk, reset : in std_logic level : in std_logic Mealy_tick, Moore_tick : out std_logic ) end edgeDetector architecture arch of edgeDetector is type stateMealy_type is ( zero, one ) - 2 states are required for Mealy signal stateMealy_reg, stateMealy_next : stateMealy_type type stateMoore_type is ( zero, edge, one ) - 3 states are required for Moore signal stateMoore_reg, stateMoore_next : stateMoore_type begin process ( clk, reset ) begin if ( reset = '1' ) then - go to state zero if reset stateMoore_reg - set 'tick = 1' if state = zero and level = '1' if level = '1' then - if level is 1, then go to state one, stateMealy_next if level = '0' then - if level is 0, then go to zero state, stateMealy_next - if state is zero, if level = '1' then - and level is 1 stateMoore_next Moore_tick if level = '0' then - if level is 0, stateMoore_next <= zero - then go to state zero. edgeDetector.vhd - Moore and Mealy Implementation library ieee use ieee.std_logic_1164. After this the sequential circuit designs using FSM are discussed in details. Then an example of these designs are shown in Section 9.3. First, Moore and Mealy designs are discussed in Section 9.2. The FSM designed can be classified as ‘Moore machine’ and ‘Mealy machine’ which are discussed in this chapter. If a system transits between finite number of such internal states, then finite state machines (FSM) can be used to design the system. The information stored in these elements can be seen as the states of the system. flip flogs or registers, are required for sequential circuits. In the other words, storage elements, e.g. In combinational circuits, the output depends on the current values of inputs only whereas in sequential circuits, the output depends on the current values of the inputs along with the previously stored information. In previous chapters, we saw various examples of the combinational circuits and sequential circuits. ![]() Regular Machine : Glitch-free Mealy and Moore design Combinational design in synchronous circuit Combinational design in asynchronous circuit
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