int a_pins[] = {14, 27, 26, 25, 33, 32, 13, 12, 23, 22, 21};
int q_pins[] = {35, 34, 15, 2 , 4 , 5 , 18, 19};
int enable   = 21;
int DS = 25;   // Serial Data
int OE = 14;   // Output Enable
int STCP = 27; // Serial Clock
int SHCP = 26; // Storage Latch

void rs_out(uint8_t bit) {
  digitalWrite(DS, bit);
  digitalWrite(STCP, HIGH);
  delay(100);
  digitalWrite(STCP, LOW);

  digitalWrite(SHCP, HIGH);
  delay(100);
  digitalWrite(SHCP, LOW);

}

uint8_t get_memory(uint16_t address) {

  digitalWrite(SHCP, LOW);
  shiftOut(DS, STCP, LSBFIRST, address);
  digitalWrite(SHCP, HIGH);
}

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  //for (int i = 0; i < 11; i++) {
  //  pinMode(a_pins[i], OUTPUT);
  //}

  for (int i = 0; i < 11; i++)
    pinMode(q_pins[i], INPUT);

  pinMode(DS, OUTPUT);
  pinMode(enable, OUTPUT);
  pinMode(OE, OUTPUT);
  pinMode(STCP, OUTPUT);
  pinMode(SHCP, OUTPUT);

  digitalWrite(enable, HIGH);
  digitalWrite(OE, LOW);
  digitalWrite(STCP, LOW);
  digitalWrite(SHCP, LOW);
  
}

int x = 0;
void loop() {
    if (x == 0) {
      get_memory(0b01010101010);
      x = 1;
    }

  // put your main code here, to run repeatedly:
  //digitalWrite(enable, HIGH);
  //delay(1000); // this speeds up the simulation
  //digitalWrite(enable, LOW);
  //delay(1000); // this speeds up the simulation
  delay(10);
}


sketch.ino

diagram.json

// Wokwi Custom Chip - For information and examples see:
// https://link.wokwi.com/custom-chips-alpha
//
// SPDX-License-Identifier: MIT
// Copyright (C) 2022 Sean D Johnston / wokwi.com

#include "wokwi-api.h"
#include <stdio.h>
#include <stdlib.h>

//#include<sys/types.h>
#include<sys/stat.h>
#include <fcntl.h>  

// Chip state
typedef struct {
  pin_t pin_a[11];
  pin_t pin_q[8];
  pin_t pin_ep;
  pin_t pin_g;

} chip_state_t;

static void chip_pin_change(void *user_data, pin_t pin, uint32_t value);
static void chip_spi_done(void *user_data, uint8_t *buffer, uint32_t count);
static void chip_timer_event(void *user_data);

/*
Initializes the chip
*/
void chip_init(void) {
  chip_state_t *chip = malloc(sizeof(chip_state_t));

  int done = 0;
  int cnt = 0;
  int bytes = 0;
  char data_key[20];
  while (!done) {
    sprintf(data_key,"data_%03x", cnt);

    string_t handle = attr_string_init(data_key);
    if (handle == 0) {
      done = 1;
    }
    else {
      uint32_t len = string_get_length(handle);
      bytes += len / 2;
      //printf("64 byte block: %s\n",data_key);
      cnt++;
      if (cnt > 0xff) break;
    }
  }

  printf("Bytes: %d\n", bytes);

  char pin_name[10];
  for (int i = 0; i < 11; i++) {
    sprintf(pin_name, "A%d", i);
    chip->pin_a[i] = pin_init(pin_name, INPUT);
  }

  for (int i = 0; i < 8; i++) {
    sprintf(pin_name, "Q%d", i);
    chip->pin_q[i] = pin_init(pin_name, OUTPUT);
    pin_write(chip->pin_q[i],HIGH);    
  }

  chip->pin_ep  = pin_init("EP-" , INPUT);
  chip->pin_g  = pin_init("G-"  , INPUT);

  // Setup watch for the load pin
  const pin_watch_config_t config = {
    .edge = BOTH,
    .pin_change = chip_pin_change,
    .user_data = chip,
  };
  pin_watch(chip->pin_ep, &config);
  pin_watch(chip->pin_g, &config);
}

/*
Check for the change of the load pin, and turns on and off the SPI data
*/
static void chip_pin_change(void *user_data, pin_t pin, uint32_t value) {
  chip_state_t *chip = (chip_state_t*)user_data;
  char pin_name[10];

  if (pin == chip->pin_g) {
    if (value == LOW) {
      printf("Enable LOW\n");
      for (int i = 0; i < 8; i++) {
        sprintf(pin_name, "Q%d", i);
        chip->pin_q[i] = pin_init(pin_name, OUTPUT);
        pin_write(chip->pin_q[i],HIGH);    
      }
    } else {
      for (int i = 0; i < 8; i++) {
        sprintf(pin_name, "Q%d", i);
        chip->pin_q[i] = pin_init(pin_name, INPUT);
        pin_write(chip->pin_q[i],HIGH);    
      }
      printf("Enable HIGH\n");
    }
  }
}

