XPT2046Adapter

Class

Source: XPT2046Adapter.h

Description

XPT2046 SPI touch controller driver

Hardware: XPT2046 (common on TFT touchscreens) Protocol: SPI — usually shares the TFT bus; ESP32-2432S028R uses a separate GPIO bit-bang bus (build with -D XPT2046_USE_GPIO_SPI; pins overridable via XPT2046_GPIO_* macros). Use -D XPT2046_GPIO_SWAP_AXES=1 when finger vertical/horizontal tracks the wrong screen axis. Use -D XPT2046_GPIO_MIRROR_X=1 when left/right are inverted (horizontal flip in screen space). GPIO path order: map → vendor swap → MIRROR_X → CAL_OFFSET_* → clamp (offsets = final nudge). Sampling: Up to 125Hz Filtering: Heavy (median + debounce + pressure threshold)

SPI bus MUST be coordinated with display DMA Requires display-specific calibration

TIP

SPI bus MUST be coordinated with display DMA

TIP

Requires display-specific calibration

Methods

static bool initImpl()

Description:

Initialize XPT2046 hardware

Returns: true if successful

static bool readImpl(TouchPoint* points, uint8_t& count)

Description:

Read touch data from XPT2046

Parameters:

• points: Output buffer
• count: Number of points read

Returns: true if successful

static void setCalibrationImpl(const TouchCalibration& calib)

Description:

Set calibration parameters

Parameters:

• calib: Calibration data

static int16_t readRawX()

Description:

Read raw X coordinate from XPT2046

Returns: Raw ADC value (0-4095)

static int16_t readRawY()

Description:

Read raw Y coordinate from XPT2046

Returns: Raw ADC value (0-4095)

static uint16_t readPressure()

Description:

Read pressure (Z) from XPT2046

Returns: Pressure value

static int16_t medianFilter(int16_t value, bool isX)

Description:

Median filter implementation

Parameters:

• value: New sample
• isX: True for X coordinate

Returns: Filtered value

static bool isConnectedImpl()

Description:

Check if controller is connected

Returns: true if responding

static bool waitForDMADone()

Description:

Wait for DMA operation to complete (SPI bus coordination)

Returns: true if bus is available, false if DMA still active

static uint32_t millis()

Description:

Platform-specific millis() function