What is the implication if a HID Touchscreen device scan time is not in 100 us units?

Hi Mark,

The primary implication of reporting scan time in arbitrary 250µs units instead of the required 100µs units is a potential failure during the Windows Hardware Lab Kit (HLK) certification testing. The HLK tests are designed to validate strict adherence to these specifications, and this deviation would likely cause the "HID Touchscreen Collection Support" test to fail, preventing your device from receiving official certification for Windows 11.

In terms of end-user functionality, the impact is less clear-cut. The operating system uses the scan time to help with power management and touch data accuracy, particularly for filtering and predicting finger movement. Using an incorrect unit could theoretically lead to minor inaccuracies in these internal calculations, but it may not be perceptible in general usage. The core touch functionality will likely still work.

To resolve this, your most straightforward path is to work with the IC vendor to inquire about a firmware update for the ILI2510-3 that corrects the unit reporting to comply with the 100µs requirement. If a firmware update is not feasible, your software driver would need to intercept and convert the reported scan time values into the correct 100µs units before they are presented to the operating system.

I hope this clarifies the implications and provides a path forward. If this answer adequately addresses your concern, please feel free to mark it as accepted. 😊