6502 address decoding PLC

JCODEC.PLD

Name            JCODEC;
Partno          JCODEC;
Revision        01;
Date            01/17/2020;
Designer        John O'Connell;
Company         ;
Location        USA;
Assembly        None;
Device          p22v10;

/****************************************************************/
/*                                                              */
/*      This is an address decoder for 6502 microprocessors     */
/*      This device will provide Enable and select signals      */
/*      for RAM, ROM and up to 4 I/O devices such as 65C22      */
/*                                                              */
/****************************************************************/

/* 
 *	Inputs:	Clock, R/W, and address lines from 65C02
 */

Pin 1  =  PHI2;
Pin 2  =  RW;
Pin 3  =  A15;
Pin 4  =  A14;
Pin 5  =  A13;
Pin 6  =  A12;
Pin 7  =  A11;
Pin 8  =  A10;
Pin 9  =  A9;
Pin 10 =  A8;
Pin 11 =  A7;
Pin 13 =  A6;
Pin 14 =  A5;
Pin 15 =  A4;


/*
 *	Outputs
 *  22V10 output logic macrocell available input terms
 *  Pin Terms
 *  14	8
 *  15	10
 *  16	12
 *  17	14
 *  18	16
 *  19	16
 *  20	14
 *  21	12
 *  22	10
 *  23	8
 */

Pin 16 = RAM;	/* RAM CS, active low */
Pin 17 = CS1;	/* VIA #1 CS, active low */
Pin 18 = CS2;	/* VIA #2 CS, active low */
Pin 19 = CS3;	/* VIA #3 CS, active low */
Pin 20 = CS4;	/* VIA #4 CS, active low */
Pin 21 = ROM;	/* ROM CS, active low */
Pin 22 = OE;	/* ROM and RAM, active low to enable output to data bus */
Pin 23 = WE;	/* ROM and RAM, active low to write to the chip from data bus */


/* 
 *  Logic:  Outputs drive active low CS pins on RAM, ROM, and VIA chips
 *  
 *  Memory Map
 *  
 *  0x0000 - 0x7FFF			32768	Bytes RAM
 *  0x8000 - 0x800F			16 		Bytes VIA 1
 *  0x8010 - 0x801F			16 		Bytes VIA 2
 *  0x8020 - 0x802F			16 		Bytes VIA 3
 *  0x8030 - 0x803F			16 		Bytes VIA 4
 *  0x8040 - 0xFFFF			32704	Bytes ROM
 */

OE	= !(PHI2 & RW);
WE	= !(PHI2 & !RW);
RAM = A15;
CS1 = ! (A15 & !A14 & !A13 & !A12 & !A11 & !A10 & !A9 & !A8 & !A7 & !A6 & !A5 & !A4 );
CS2 = ! (A15 & !A14 & !A13 & !A12 & !A11 & !A10 & !A9 & !A8 & !A7 & !A6 & !A5 & A4 );
CS3 = ! (A15 & !A14 & !A13 & !A12 & !A11 & !A10 & !A9 & !A8 & !A7 & !A6 & A5 & !A4 );
CS4 = ! (A15 & !A14 & !A13 & !A12 & !A11 & !A10 & !A9 & !A8 & !A7 & !A6 & A5 & A4 );
ROM = ! (A15 & ( A14 # A13 # A12 # A11 # A10 # A9 # A8 # A7 # A6 ));

JCODEC.SI

Name     JCODEC;
PartNo   JCODEC;
Date     01/17/2020;
Revision 01;
Designer John O'Connell;
Company  ;
Assembly None;
Location USA;
Device   p22v10;


ORDER: PHI2, RW, A15, A14, A13, A12, A11, A10, A9, A8, A7, A6, A5, A4, WE, OE, RAM, CS1, CS2, CS3, CS4, ROM; 


VECTORS:
00000000000000********
10000000000000********
00000000000000********
01000000000000********
11000000000000********
01000000000000********
01011111111111********
01100000000000********
01100000000001********
01100000000010********
01100000000011********
01100000000100********
01111111111111********

JCODEC.SO

CSIM(WM): CUPL Simulation Program
Version 5.0a Serial# 
Copyright (c) 1983, 1998 Logical Devices, Inc.
CREATED Sat Jan 18 16:01:33 2020

LISTING FOR SIMULATION FILE: JCODEC.si

   1: Name     JCODEC;
   2: PartNo   JCODEC;
   3: Date     01/17/2020;
   4: Revision 01;
   5: Designer John O'Connell;
   6: Company  ;
   7: Assembly None;
   8: Location USA;
   9: Device   p22v10;
  10: 
  11: 
  12: ORDER: PHI2, RW, A15, A14, A13, A12, A11, A10, A9, A8, A7, A6, A5, A4, WE, OE, RAM, CS1, CS2, CS3, CS4, ROM; 
  13: 
  14: 

===============================
      P                        
      H AAAAAA        RCCCCR   
      IR111111AAAAAAWOASSSSO   
      2W543210987654EEM1234M   
===============================
0001: 00000000000000HHLHHHHH
0002: 10000000000000LHLHHHHH
0003: 00000000000000HHLHHHHH
0004: 01000000000000HHLHHHHH
0005: 11000000000000HLLHHHHH
0006: 01000000000000HHLHHHHH
0007: 01011111111111HHLHHHHH
0008: 01100000000000HHHLHHHH
0009: 01100000000001HHHHLHHH
0010: 01100000000010HHHHHLHH
0011: 01100000000011HHHHHHLH
0012: 01100000000100HHHHHHHL
0013: 01111111111111HHHHHHHL

Tester.ino

const char ADDR[] = {22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52}; // A15..A0
const char DATA[] = {39, 41, 43, 45, 47, 49, 51, 53};                                 // D7..D0

#define CLOCK   2
#define RW      3

#define WE      23
#define OE      25
#define ROM     27
#define CS4     29
#define CS3     31
#define CS2     33
#define CS1     35
#define RAM     37


void setAddress(word address) {
  for ( int i=15; i >= 0; i-- ) {
    digitalWrite(ADDR[i], address & 1);
    address = address >> 1;
  }
}

void checkPrint(word address) {
  bool wri_EN = digitalRead(WE);
  bool out_EN = digitalRead(OE);
  bool rom_CS = digitalRead(ROM);
  bool ram_CS = digitalRead(RAM);;
  bool va1_CS = digitalRead(CS1);
  bool va2_CS = digitalRead(CS2);
  bool va3_CS = digitalRead(CS3);
  bool va4_CS = digitalRead(CS4);

  char output[128];

  sprintf(output, " Address %04x - OE:%c WE:%c RAM:%c CS1:%c CS2:%c CS3:%c CS4:%c ROM:%c",
          address,
          out_EN ? '+' : '-',
          wri_EN ? '+' : '-',
          ram_CS ? '+' : '-',
          va1_CS ? '+' : '-',
          va2_CS ? '+' : '-',
          va3_CS ? '+' : '-',
          va4_CS ? '+' : '-',
          rom_CS ? '+' : '-');

  Serial.println(output);
}

void setup() {

//Pin modes
  for( int i = 0; i < 16; i++ ) {
    pinMode(ADDR[i], OUTPUT);
  }
  for( int i = 0; i < 8; i++ ) {
    pinMode(DATA[i], INPUT);
  }

  for(int i=0; i<16; i++) {
    digitalWrite(ADDR[i], LOW);
  }

  pinMode(CLOCK,OUTPUT);
  pinMode(RW,OUTPUT);

  digitalWrite(CLOCK, LOW);
  digitalWrite(RW, HIGH);

  pinMode(WE,INPUT);
  pinMode(OE,INPUT);
  pinMode(ROM,INPUT);
  pinMode(CS4,INPUT);
  pinMode(CS3,INPUT);
  pinMode(CS2,INPUT);
  pinMode(CS1,INPUT);
  pinMode(RAM,INPUT);

  Serial.begin(57600);

  Serial.println("Read RAM 0x0000");
  setAddress(0x0000);
  digitalWrite(RW, HIGH);
  digitalWrite(CLOCK, HIGH);
  checkPrint(0x0000);

  Serial.println("Write RAM 0x0101");
  setAddress(0x0101);
  digitalWrite(RW, LOW);
  checkPrint(0x0101);

  Serial.println("Top of RAM");
  setAddress(0x7FFF);
  digitalWrite(RW, HIGH);
  checkPrint(0x7FFF);

  Serial.println("Interface #1");
  setAddress(0x8000);
  checkPrint(0x8000);

  Serial.println("Interface #2");
  setAddress(0x8010);
  checkPrint(0x8010);

  Serial.println("Interface #3");
  setAddress(0x8020);
  checkPrint(0x8020);

  Serial.println("Interface #4");
  setAddress(0x8030);
  checkPrint(0x8030);

  Serial.println("Bottom of ROM");
  setAddress(0x8040);
  checkPrint(0x8040);

  Serial.println("Top of ROM");
  setAddress(0xFFFF);
  checkPrint(0xFFFF);

}

void loop() {
}