Name     6502uart ;
PartNo   00 ;
Date     21/07/2004 ;
Revision 01 ;
Designer Philip Pemberton ;
Company  Philpem ;
Assembly None ;
Location IC2 ;
Device   g16v8as ;

/************************************************************************/
/* This device generates the chip select signals for the UART on the    */
/* 16550 UART board                                                     */
/* Chip: GAL16V8A (Simple PLD mode)                                     */
/************************************************************************/

/* *************** INPUT PINS *********************/
PIN   1 = !RST                    ; /* Reset                           */ 
PIN   2 = SEL0                    ; /* Select 0                        */ 
PIN   3 = SEL1                    ; /* Select 1                        */ 
PIN   4 = SEL2                    ; /* Select 2                        */ 
PIN   5 = RW                      ; /* Read/!Write                     */ 
PIN   6 = PHI2                    ; /* Phase 2 Clock                   */ 

FIELD SEL = [SEL0..SEL2];

/* *************** OUTPUT PINS *********************/
PIN  19 = MR                      ; /* Master Reset                    */ 
PIN  18 = !CS2                    ; /* Chip Select                     */ 
PIN  17 = !WR                     ; /* Write                           */ 
PIN  16 = !RD                     ; /* Read                            */ 

/* ************ INTERMEDIATE EQUATIONS *************/
READ  = RW;
WRITE = !RW;

/* ************* LOGIC EQUATIONS *******************/
/* Master Reset */
MR = RST;

/* Chip Select, Write and Read */
CS2 = SEL:1 & PHI2;
WR  = CS2   & WRITE;
RD  = CS2   & READ;