-- Copyright © 1993 by  McGraw-Hill, Inc. and Zainalabedin Navabi

-- FIGURE 6.27 




-- ENTITY DECLARATION OF INV_RC :

USE WORK.basic_utilities.ALL;
ENTITY inv_rc IS
  GENERIC (c_load : capacitance := 66 ffr);
  PORT (i1 : IN qit; o1 : OUT qit);
  CONSTANT rpu : resistance := 25 k_o; 
  CONSTANT rpd : resistance := 15 k_o;
END inv_rc;
--



-- DOUBLE DELAY ARCHITECTURE OF INV_RC :

ARCHITECTURE double_delay OF inv_rc IS
  CONSTANT tplh : TIME := rpu * c_load * 3 FS;
  CONSTANT tphl : TIME := rpd * c_load * 3 FS;
BEGIN
  o1 <= '1' AFTER tplh WHEN i1 = '0' ELSE
        '0' AFTER tphl WHEN i1 = '1' OR i1 = 'Z' ELSE
        'X' AFTER tplh;
END double_delay;
--