DCC-Bench/ESP32-2432S028R_MIGRATION.md

ESP32-2432S028R Migration Summary

Overview

Successfully migrated the DCC-Bench project from WiFi/WebServer control to touchscreen-based control using the ESP32-2432S028R module (ESP32 with ILI9341 TFT touchscreen).

Hardware Configuration

ESP32-2432S028R Module

• Board: ESP32-WROOM-32
• Display: ILI9341 TFT (320x240 pixels)
• Touch: XPT2046 resistive touchscreen
• Pins Used:
  • TFT MISO: GPIO 12
  • TFT MOSI: GPIO 13
  • TFT SCLK: GPIO 14
  • TFT CS: GPIO 15
  • TFT DC: GPIO 2
  • TFT BL (Backlight): GPIO 21
  • Touch CS: GPIO 22
  • Relay Control: GPIO 4
  • PWM/DCC_A: GPIO 18 (dual purpose)
  • DIR/DCC_B: GPIO 19 (dual purpose)
  • Motor BRAKE: GPIO 23

LM18200 H-Bridge Driver (Dual Purpose)

The LM18200 serves as BOTH the DC motor controller AND DCC signal booster:

• DC Analog Mode: GPIO 18 sends PWM for speed, GPIO 19 sets direction
• DCC Digital Mode: GPIO 18 sends DCC signal A, GPIO 19 sends DCC signal B (inverted)
• Same hardware, different signals depending on mode selected
• LM18200 amplifies the 3.3V logic signals to track voltage (12-18V)

Key Changes

1. PlatformIO Configuration (platformio.ini)

• Changed: Board target from esp32doit-devkit-v1 to esp32dev for ESP32-2432S028R
• Removed: WiFi/WebServer libraries (ESPAsyncWebServer, AsyncTCP)
• Added:
  • bodmer/TFT_eSPI@^2.5.43 - Display driver
  • paulstoffregen/XPT2046_Touchscreen@^1.4 - Touch controller
• Added: TFT_eSPI build flags for ILI9341 configuration

2. New Components

RelayController (RelayController.h/cpp)

• Controls relay on GPIO 27 for 2-rail/3-rail track switching
• Simple HIGH/LOW control
• State tracking and persistence through Config

TouchscreenUI (TouchscreenUI.h/cpp)

• Full graphical user interface with touch controls
• Features:
  • Power ON/OFF button (green/red indicator)
  • DCC/Analog mode toggle button (cyan/yellow)
  • 2-Rail/3-Rail selector button
  • Direction control (FWD/REV)
  • Horizontal speed slider (0-100%)
  • Status bar showing all current settings
• Behavior:
  • Switching from DCC to Analog (or vice versa) automatically powers off the system
  • All settings are saved to NVS (persistent storage)
  • Touch events mapped to screen coordinates with calibration

3. Modified Components

Config (Config.h/cpp)

• Removed: All WiFi-related configuration (WiFiConfig struct)
• Added to SystemConfig:
  • bool is3Rail - Track configuration (2-rail/3-rail)
  • bool powerOn - Power state tracking
• Updated: Save/load methods to persist new settings

Main (main.cpp)

• Removed: WiFi, WebServer, LEDIndicator components
• Added: TouchscreenUI, RelayController
• Updated: Setup sequence and main loop
• Simplified: Loop now only handles UI updates and motor/DCC control based on power state

4. Removed Files

• include/WiFiManager.h
• src/WiFiManager.cpp
• include/WebServer.h
• src/WebServer.cpp
• include/LEDIndicator.h (was already commented out)

User Interface Layout

┌─────────────────────────────────────────────────┐
│ [POWER] [MODE ] [RAILS] [DIR ]                  │
│  ON/OFF  DCC/DC 2/3Rail FWD/REV                 │
│                                                  │
│              Speed: 45%                          │
│                                                  │
│  ╔════════════════○═════════════╗               │
│  ║                               ║  Speed Slider│
│  ╚═══════════════════════════════╝               │
│                                                  │
│ ┌─────────────────────────────────────────────┐ │
│ │ PWR:ON | Mode:DCC | 3-Rail | Addr:3         │ │
│ │ Speed:45% FWD                                │ │
│ └─────────────────────────────────────────────┘ │
└─────────────────────────────────────────────────┘

Features Implemented

✅ Power Control

• Power ON/OFF button
• Safety: Power automatically turns OFF when switching between DCC and Analog modes
• Power state persisted in configuration

✅ Mode Switching

• Toggle between DCC and DC Analog control
• Visual indication (Cyan for DCC, Yellow for Analog)
• Automatic power-off on mode change prevents unsafe transitions

✅ Rail Configuration

• 2-Rail / 3-Rail selector
• Physical relay control on GPIO 27
• Energized = 3-Rail, De-energized = 2-Rail

✅ Speed Control

• Interactive horizontal slider
• Range: 0-100%
• Real-time speed updates to motor/DCC controller
• Visual feedback with active/inactive portions

✅ Direction Control

• Forward/Reverse toggle
• Updates motor or DCC direction based on current mode

✅ Persistent Storage

• All settings saved to ESP32 NVS (Non-Volatile Storage)
• Settings persist across power cycles
• Automatic save on every change

Building and Uploading

# Install dependencies and build
pio run

# Upload to ESP32-2432S028R
pio run --target upload

# Monitor serial output
pio device monitor

Next Steps / Future Enhancements

1. DCC Address Entry: Add touchscreen numeric keypad for changing DCC address
2. Function Buttons: Add DCC function controls (F0-F12) with toggle buttons
3. Speed Presets: Add quick-access speed buttons (25%, 50%, 75%, 100%)
4. Track Current Monitoring: Display track current if current sensor is added
5. Emergency Stop: Large red emergency stop button
6. Locomotive Profiles: Save/load different locomotive configurations

Testing Checklist

• Display initializes correctly
• Touch calibration is accurate
• Power button toggles ON/OFF
• Mode switch changes DCC/Analog
• Mode switch automatically powers off
• Rail selector controls relay
• Speed slider adjusts output
• Direction button changes FWD/REV
• Settings persist after reboot
• DCC signals generated correctly (when powered on)
• DC motor control works (when powered on)
• Relay switches correctly

Pin Reference

Function	GPIO	Notes
PWM/DCC_A	18	DC: 20kHz PWM / DCC: Signal A
DIR/DCC_B	19	DC: Direction / DCC: Signal B
Motor Brake	23	Active LOW brake
Relay Control	4	HIGH=3-Rail, LOW=2-Rail
TFT MISO	12	SPI data in
TFT MOSI	13	SPI data out
TFT SCLK	14	SPI clock
TFT CS	15	Chip select
TFT DC	2	Data/Command
TFT Backlight	21	Backlight control
Touch CS	22	Touch chip select

Notes

• Motor PWM frequency: 20kHz (silent operation)
• Display orientation: Landscape (320x240)
• Touch type: Resistive (XPT2046)
• All configuration stored in NVS partition
• Pin assignments avoid conflicts with ESP32-2432S028R built-in peripherals