text: /*****************************************************************************
  
    74153 Dual 4-line to 1-line data selectors/multiplexers
  
  
    Pin layout and functions to access pins:
  
    enable_w(0)        [1] /1G   VCC [16]
    b_w                [2] B     /2G [15]  enable_w(1)
    input_line_w(0,3)  [3] 1C3	 A [14]  a_w
    input_line_w(0,2)  [4] 1C2   2C3 [13]  input_line_w(1,3)
    input_line_w(0,1)  [5] 1C1   2C2 [12]  input_line_w(1,2)
    input_line_w(0,0)  [6] 1C0   2C1 [11]  input_line_w(1,1)
    output_r(0)        [7] 1Y	   2C0 [10]  input_line_w(1,0)
  	                 [8] GND    2Y [9]   output_r(1)
  
  
    Truth table (all logic levels indicate the actual voltage on the line):
  
    	        INPUTS         | OUTPUT
                             |
  	G | B  A | C0 C1 C2 C3 | Y
  	--+------+-------------+---
  	H |	X  X | X  X  X  X  | L
   	L | L  L | X  X  X  X  | C0
   	L | L  H | X  X  X  X  | C1
   	L | H  L | X  X  X  X  | C2
   	L | H  H | X  X  X  X  | C3
  	--+------+-------------+---
  	L	= lo (0)
  	H	= hi (1)
  	X	= any state
  
  *****************************************************************************/
  
  #ifndef TTL74153_H
  #define TTL74153_H
  
  
  /* The interface structure */
  struct TTL74153_interface
  {
  	void (*output_cb)(void);
  };
  
  
  void TTL74153_config(int which, const struct TTL74153_interface *intf);
  
  /* must call TTL74153_update() after setting the inputs */
  void TTL74153_update(int which);
  
  void TTL74153_a_w(int which, int data);
  void TTL74153_b_w(int which, int data);
  void TTL74153_input_line_w(int which, int section, int input_line, int data);
  void TTL74153_enable_w(int which, int section, int data);
  int TTL74153_output_r(int which, int section);
  
  #endif
  