Cheng & RubyCircuit
RubyCircuit
Cheng, I've been tinkering with the idea of a microcontroller driven puzzle that lets you solve logic gates by wiring LEDs, think of it as a hardware escape room. I’m thinking of using an ESP32 with an OLED, and I need to iron out the timing of the state machine for the solver. You up for debugging this together?
Cheng
Sounds like a fun challenge, let’s dive in—first things first, make sure your clock source is stable, otherwise the state machine will act like a squirrel on espresso. Then we can lock down the debounce windows for the button inputs, because nobody wants a flaky circuit that thinks it’s a game of Simon. Ready to sketch out the state diagram together?
RubyCircuit
Sure, let's nail it down. Start with a 32 MHz external crystal for the ESP32, lock it in, and use the internal RC for low‑power mode if needed. Then map the state machine: IDLE → READ_INPUT → EVAL_GATES → OUTPUT_LED. Keep each transition bounded by a 10 ms debounce on the buttons. Once you’ve drafted that, send me the code and I’ll spot any race conditions.
Cheng
```c
#include <Arduino.h>
#include <Wire.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
#define BUTTON_PIN 15
#define LED_PIN 2
enum State {IDLE, READ_INPUT, EVAL_GATES, OUTPUT_LED};
volatile State currentState = IDLE;
unsigned long lastDebounce = 0;
const unsigned long debounceDelay = 10; // ms
bool buttonPressed = false;
// Simple gate example: AND of two inputs
bool inputA = false;
bool inputB = false;
bool result = false;
// Pin setup
void setupPins() {
pinMode(BUTTON_PIN, INPUT_PULLUP);
pinMode(LED_PIN, OUTPUT);
digitalWrite(LED_PIN, LOW);
}
// Read button with debounce
void checkButton() {
bool reading = !digitalRead(BUTTON_PIN); // active low
if (reading != buttonPressed) {
lastDebounce = millis();
buttonPressed = reading;
}
if ((millis() - lastDebounce) > debounceDelay && buttonPressed) {
buttonPressed = false; // reset flag
// toggle one of the inputs
inputA = !inputA;
}
}
// State machine loop
void loopStateMachine() {
switch (currentState) {
case IDLE:
if (digitalRead(BUTTON_PIN) == LOW) { // button pressed
currentState = READ_INPUT;
}
break;
case READ_INPUT:
checkButton();
currentState = EVAL_GATES;
break;
case EVAL_GATES:
// Example: AND gate
result = inputA && inputB;
currentState = OUTPUT_LED;
break;
case OUTPUT_LED:
digitalWrite(LED_PIN, result ? HIGH : LOW);
// Show status on OLED
display.clearDisplay();
display.setTextSize(1);
display.setTextColor(SSD1306_WHITE);
display.setCursor(0,0);
display.print("A:");
display.print(inputA ? "1" : "0");
display.print(" B:");
display.print(inputB ? "1" : "0");
display.print(" OUT:");
display.println(result ? "1" : "0");
display.display();
currentState = IDLE;
break;
}
}
void setup() {
Serial.begin(115200);
// Configure crystal oscillator (assumed set in SDK)
// Switch to internal RC for low-power when needed via sleep routines (not shown)
setupPins();
if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
Serial.println(F("SSD1306 allocation failed"));
for(;;);
}
display.clearDisplay();
display.display();
}
void loop() {
loopStateMachine();
}
```