Fixing Inverted Touchscreen On ESP32-U With Bruce Firmware

by Admin 59 views
Fixing Inverted Touchscreen on ESP32-U with Bruce Firmware

Hey guys! So, you're having trouble with your touchscreen on your ESP32-U board, huh? Specifically, the touch input is inverted when using Bruce Firmware v1.11.1 and a 2.8" CYD (ILI9341) display. Don't worry, we've all been there! It's super frustrating when the screen works perfectly, but the touch coordinates are all messed up. Let's dive in and see how we can fix this. We'll explore the problem, the setup, the common pitfalls, and hopefully, find a solution to get your touchscreen working correctly. This guide will walk you through the troubleshooting steps, potential configuration changes, and a bit about the underlying issues that might be causing this inverted behavior. This is crucial for anyone trying to implement this kind of setup; it is also a good opportunity to learn more about how touchscreens integrate with embedded systems.

Understanding the Problem: Inverted Touch Coordinates

The core issue here is that the touchscreen's X and Y coordinates are flipped or mirrored, making it impossible to accurately interact with the UI. You touch one part of the screen, and the system registers a touch somewhere else entirely. This happens because the firmware isn't correctly interpreting the touch data from the screen. It's like looking in a mirror that flips everything horizontally and vertically – not very useful! This can manifest in a couple of ways: the X-axis might be mirrored (left becomes right, and vice-versa), the Y-axis might be mirrored (top becomes bottom, and vice-versa), or both axes might be swapped (X and Y are switched). In this specific case, the user reports both X and Y axes are flipped. Knowing the exact nature of the inversion (X-axis, Y-axis, or both) is crucial in debugging the problem and applying the right fix. This highlights the importance of understanding coordinate systems and how they relate to the physical layout of your touchscreen.

This problem often stems from misconfiguration or a lack of calibration within the firmware. The Bruce Firmware might not be correctly configured to handle the specific touchscreen controller or the wiring configuration. Sometimes, the issue is as simple as a setting that needs to be toggled, but other times, it requires a deeper dive into the configuration files or even the firmware code itself. The user has already identified that screen rotation in bruce.conf doesn't affect the touch, which suggests the problem lies in the touch input mapping rather than the display output. This indicates that the system is properly displaying information, but the touchscreen data is being misinterpreted. To solve this, we will review the wiring, the software, and look at the configuration settings and how they interact to handle touch input.

Hardware Setup: ESP32-U, CYD Display, and Wiring

Let's take a look at the hardware setup. The user is using an ESP32-U board and a 2.8" CYD display. The wiring is provided, which is great because it gives us a clear picture of how everything is connected. The wiring is the foundation, and any errors here can lead to problems. The most critical connections are those related to the touch functionality: T_IRQ, T_DO, T_DIN, T_CS, and T_CLK. These pins are essential for the ESP32-U to communicate with the touchscreen controller and receive touch data. Make sure all these connections are secure and correctly wired according to the specifications of both the ESP32-U and the CYD display. Incorrect wiring is a common cause of touchscreen issues. Double-check everything before proceeding. Also, the display connections for data, command, reset, chip select, and backlight are important for display operations and could be related to your issue.

Here’s a breakdown of the wiring provided:

  • T_IRQ (VP): Touch Interrupt - This pin signals the ESP32 when the screen is touched. It's crucial for responsiveness.
  • T_DO (VN): Touch MISO (Master In Slave Out) - Data from the touchscreen to the ESP32.
  • T_DIN (32): Touch MOSI (Master Out Slave In) - Data from the ESP32 to the touchscreen.
  • T_CS (33): Touch Chip Select - Selects the touchscreen for communication.
  • T_CLK (25): Touch Clock - Provides the clock signal for data transfer.
  • SDO (12): TFT MISO - Display data from the display to the ESP32.
  • LED (21): Backlight control.
  • SCK (14): TFT Clock - Clock signal for the display.
  • SDI (13): TFT MOSI - Display data from the ESP32 to the display.
  • DC (2): Data/Command - Selects between data and command mode for the display.
  • RESET (EN): Display Reset - Resets the display.
  • CS (15): Display Chip Select - Selects the display.
  • GND: Ground - Power and signal ground.
  • VCC (3V3): Power - Power supply (3.3V).

The reference to the D.I.Y. Cheap Yellow Display for Bruce schematic is helpful. Use this to ensure that your wiring matches the expected connections for this setup. Make sure your hardware setup matches the schematic for this particular display.

Potential Hardware Issues

  • Loose connections: Ensure all wires are securely connected to the ESP32-U and the CYD display. Loose connections are a common source of intermittent problems.
  • Incorrect pin assignments: Double-check that the pins are wired according to the correct specifications for both the ESP32-U and the CYD display. Incorrect pin assignments can cause a variety of issues, including incorrect touch input.
  • Power issues: Ensure your ESP32-U and CYD display are receiving adequate power. Undervoltage can lead to erratic behavior.

Software Configuration and Troubleshooting with Bruce Firmware

Alright, let's talk about the software side of things, specifically the Bruce Firmware. Configuration files are the key to customizing the firmware behavior, including touchscreen settings. The user has already tried adding touch_invert_x, touch_invert_y, and touch_swap_xy to the config files, but unfortunately, they were ignored or overwritten. This is a common issue when settings aren't correctly applied or when there is a conflict with other settings or initialization sequences within the firmware. Let's investigate the configuration files further. Where these settings are defined is often the source of conflict. The bruce.conf file, and other related configuration files that Bruce Firmware uses, determine how the touchscreen data is interpreted. Finding the correct configuration files is crucial, and it’s important to understand how these files interact with the firmware’s core logic. The user needs to verify the correct file being modified and ensure the modifications are being read during startup.

Configuration File Analysis

  • Locate the Correct Configuration File: The first step is to identify the main configuration file that controls the touchscreen settings. The user has already modified bruce.conf, but it's possible that this file is not being read or that the settings within it are being overridden by other configurations. Look for any other configuration files that might influence the touchscreen behavior. The exact location of this file depends on the Bruce Firmware version and the build process. Check the firmware documentation or the Bruce Firmware project for details on the configuration files.
  • Examine the Touchscreen Settings: Carefully review the settings related to the touchscreen. Look for parameters that control the X and Y axis inversion or swapping. The presence of touch_invert_x, touch_invert_y, and touch_swap_xy indicates that the firmware offers configuration options for controlling the touch input's orientation. Confirm the syntax, format, and value ranges for these settings in the configuration file. The settings should match the instructions provided by the Bruce Firmware documentation.
  • Check for Overriding Settings: Ensure that no other settings are overriding your configuration. Sometimes, default values in the firmware might take precedence over the settings in your configuration file. Look for any initialization code or default settings that might interfere with your custom configuration. You might need to adjust the order in which the configuration files are loaded, or you might need to change the firmware code itself to properly configure the touch input.

Firmware Code Exploration (If Necessary)

If you can't find a solution through configuration, you might need to look at the firmware code itself. You need to understand how the touch input is handled within the firmware. This might involve diving into the code that initializes the touchscreen controller, reads the touch data, and maps it to the display coordinates. Finding the relevant source code files and functions will be the first step in this process. You need to be comfortable with C/C++ to work with the firmware.

  • Locate the Touchscreen Driver: Find the code responsible for reading and interpreting the touch data from the CYD (ILI9341) touchscreen controller. The driver will likely be responsible for initializing the touch controller, reading the touch coordinates, and scaling them to match the display resolution. Locate the driver code for the ILI9341 display.
  • Analyze the Coordinate Mapping: Once you've located the driver, examine how the touch coordinates are mapped to the display coordinates. The driver might contain functions or calculations that convert the raw touch data to screen coordinates. Identify any areas where the X and Y axes might be inverted or swapped. If the driver does not have inverting options, you might need to add them or modify the existing code to implement it.
  • Implement Touch Inversion (If Necessary): If the firmware doesn't provide built-in inversion options, you might need to modify the code to implement them. This could involve swapping the X and Y coordinates, inverting the X-axis, inverting the Y-axis, or a combination of these operations. Make sure to test your changes thoroughly after implementing any code modifications. The goal is to ensure the changes are applied correctly.

Calibration and Testing

Calibration is a critical step in ensuring the touchscreen works correctly. If the touch input is still off, you can try calibration. It’s like teaching the system where the screen's corners and center are so it can accurately map your touches. Some firmware might have a built-in calibration feature. If the firmware has a calibration feature, use it. Calibration allows the system to adjust for any minor variations in the screen's physical alignment and provides for precise touch input.

  • Calibration Process: Follow the instructions provided by the Bruce Firmware to calibrate the touchscreen. This usually involves touching specific points on the screen as prompted by the firmware. Calibration often involves touching corners or crosshairs on the display to allow the system to map touch inputs accurately. The purpose is to refine the mapping of touch coordinates to the display.
  • Testing: Test the touchscreen after applying changes or calibrations. Carefully check all corners and the center of the screen to ensure the touch input matches the display output. Test the screen’s responsiveness. You might need to repeat the calibration and testing steps until you achieve satisfactory results.

Potential Solutions and Workarounds

Let’s summarize the potential solutions. Remember, it might take a combination of these approaches to solve the issue.

  1. Double-check the wiring: Make sure everything is wired correctly, and all connections are secure, as detailed above in the hardware section.
  2. Verify Configuration Files: Make sure the configuration files are in the right location and the changes are applied correctly.
  3. Use correct syntax. Double-check the syntax of the touch inversion settings in your configuration file and ensure they are correct (e.g., touch_invert_x = 1).
  4. Calibration: Attempt the touchscreen calibration within the Bruce Firmware. The calibration process is crucial for mapping the touch coordinates accurately.
  5. Examine the Firmware Code: If the config changes don’t work, explore the firmware code. The touch driver might need modifications to invert the touch input.
  6. Update Firmware: Consider updating to the latest version of Bruce Firmware to ensure you have the latest features and bug fixes.

By following these steps, you should be able to troubleshoot and resolve the inverted touchscreen issue on your ESP32-U with Bruce Firmware and the CYD 2.8" display. Good luck, guys, and happy tinkering!