Name            ADC-12 Expansion Module ;
Partno          None ;
Revision        02 ;
Date            2/01/93 ;
Designer        Tom Bachmann ;
Company         Blue Earth Research ;
Assembly        None ;
Location        None ;
Device          P18CV8 ;        /*  AMI/GOULD PEEL18CV8  */


/************************************************************************/
/* This device generates chip select signals for the A/D expander.      */
/************************************************************************/

/** Inputs **/

Pin 1           = CLOCKIN ;             /* Register clock               */
Pin [2..9]      = [A8..15] ;            /* Address inputs A8 thru A15   */
Pin 11          = OEIN ;                /* Output enable input          */
Pin 13          = WR ;                  /*                              */

/** Outputs **/

Pin 12          = W_P_ ;                /* W.P. to Micro-440            */
Pin 14          = WPOUT ;               /* Write protect output         */
Pin 15          = SPARE ;               /*                              */
Pin 16          = !Chip ;               /* Chip select                  */
Pin 17          = SFR ;                 /* Special function register    */
Pin 18          = HBE ;                 /* High byte enable             */
Pin 19          = CLOCKOUT ;            /* Decoded clock signal         */


/** Declarations and Intermediate Variable Definitions  **/

Field   Addr    = [A8..15] ;

/** Logic Equations **/

/*  Micro-440 peripheral map:   FF00H = ADC0848CCV A/D                  */
/*                              FE00H = RTC-72423B Clock                */

CLOCKOUT        = Addr:[D000..D700] & !WR ;

HBE.D           = A8 ;
HBE.AR          = OEIN ;
HBE.SP          = OEIN ;
SFR.D           = A9 ;
SFR.AR          = OEIN ;
SFR.SP          = OEIN ;
WPOUT.D         = A10 ;
WPOUT.AR        = OEIN ;
WPOUT.SP        = OEIN ;

W_P_            = WPOUT & Addr:[6000..7F00] ;

Chip            = Addr:[D800] ;