DigitalCircuits - Digital Circuits Basic Concepts Simple...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Jon Turner/ David M. Zar Simple binary calculator Basic circuit elements Specifying circuits with hardware description languages Using simulation to verify circuit operation Logic equations and combinational circuits Digital Circuits – Basic Concepts
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
‹#› A Simple Binary Calculator Three operations » clear stored value » load new value » add to stored value Components » flip flops store information » multiplexor selects 1-of-2 inputs » adder computes sum D in add 1 0 Adder load clear D >C Q result 8 8 8 8 clk D flip-flops multiplexor 1 0 1 0 x00
Background image of page 2
‹#› Basic Circuit Elements AND gate A B A · B A B A + B OR gate A A inverter 0 1 C X 0 A 1 B A B X=C · A + C · B C 2:1 multiplexor D flip-flop D >C Q D clk store value of D on rising clock edge AB A·B A+B A’ 00 0 0 1 01 0 1 1 10 0 1 0 11 1 1 0 truth table for logic gates 2 2 2 is shorthand for 2 2 is shorthand for for gates and mux, outputs change as inputs change for flip flop, output changes only at clock edge
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
‹#› VHDL Specification of Calculator entity calculator is port ( clk: in std_logic; clear, load, add: in std_logic; -- operation signals dIn: in std_logic_vector(7 downto 0); -- input data result: out std_logic_vector(7 downto 0)); -- output result end calculator; architecture a1 of calculator is signal dReg: std_logic_vector(7 downto 0); begin process (clk) begin if rising_edge(clk) then if clear = '1' then dReg <= x"00"; elsif load = '1' then dReg <= dIn; elsif add = '1' then dReg <= dReg + dIn; end if; end if; end process; result <= dReg; end a1; stored value synchronization condition synchronized assignments
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 11/06/2011.

Page1 / 15

DigitalCircuits - Digital Circuits Basic Concepts Simple...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online