Calibration must persist across sleep/resume:
KdPrintEx((DPFLTR_IHVDRIVER_ID, DPFLTR_TRACE_LEVEL, "Raw: (%d, %d) -> Calibrated: (%d, %d)\n", rawX, rawY, calibratedX, calibratedY)); Use code with caution. Step 3: Use the Windows Hardware Lab Kit (HLK)
Ycalibrated=(Yraw−MinY)×32767(MaxY−MinY)cap Y sub c a l i b r a t e d end-sub equals the fraction with numerator open paren cap Y sub r a w end-sub minus cap M i n cap Y close paren cross 32767 and denominator open paren cap M a x cap Y minus cap M i n cap Y close paren end-fraction Note: Windows uses a 0-32767 range for touchscreen input. 4. Testing and Validation kmdf hid minidriver for touch i2c device calibration
Ycal=D⋅Xraw+E⋅Yraw+Fcap Y sub c a l end-sub equals cap D center dot cap X sub r a w end-sub plus cap E center dot cap Y sub r a w end-sub plus cap F are the calibration coefficients. Implementing the Calculation in Kernel Mode
A HID minidriver is a specialized driver that enables a HID device to communicate with the Windows operating system. HID devices, such as touchscreens, mice, and keyboards, are designed to provide an intuitive interface for users to interact with their computers. The HID minidriver acts as a bridge between the device and the operating system, facilitating data exchange and device control. Testing and Validation Ycal=D⋅Xraw+E⋅Yraw+Fcap Y sub c a
// User-mode application sends: HidD_SetFeature( handle, reportBuffer, // contains: command (READ_CALIBRATION) + offset + length bufferLength );
VOID MyTouchCalibReadComplete( WDFREQUEST Request, WDFIOTARGET Target, PWDF_REQUEST_COMPLETION_PARAMS Params, WDFCONTEXT Context) The HID minidriver acts as a bridge between
The is a set of libraries that simplify Windows driver development. A HID Minidriver is a lower-level driver that handles the specifics of a particular transport (in this case, I2Ccap I squared cap C
CALIBRATION_DATA* calib = GetCalibrationContext(); USHORT calX = (USHORT)(rawX * calib->x_gain + calib->x_offset); USHORT calY = (USHORT)(rawY * calib->y_gain + calib->y_offset);
The KMDF minidriver must expose specialized Input/Output Controls (IOCTLs) that allow user-mode applications to send calibration data down to the device. 2. The Calibration Tool
Uses a "Golden Matrix" defined during factory testing to compensate for known hardware variances.