11.3 Functional Description

The scroller module processing is dependent on the touch key module output. After the keys are processed and statuses are updated in the data structures, they are checked by the slider module. Based on the key status, the slider/wheel position is calculated from the current signal values available on the acquisition module variables.

The possible use cases and the sequence of operations under each use case are given below.

Use Case 1: Touch contact made on slider/wheel sensor

  1. The module checks the status of all keys in the scroller for touch contact detection.
  2. If any key is in the detect state, the touch position is calculated using the signal values of three adjacent keys.
  3. Both raw position and filtered position are calculated.
  4. The scroller state comes to “TOUCH_ACTIVE”, and the scroller reburst flag is set.
  5. The “POSITION_CHANGE” flag is set now. The flag is cleared on the next measurement cycle if the touch is stationary and no change in touch position.

Use Case 2: Touch contact scrolling over the slider/wheel surface

  1. The module checks all keys for touch contact.
  2. If no key is in detect, the module searches for a pair of neighboring keys whose touch delta exceeds the minimum contact threshold.
  3. If such a contact is found, then the new position is calculated.

    Or

  4. If no such contact is found, the scroller returns to ‘No Detect’ condition.

Use Case 3: Touch contact removed from slider/wheel sensor

  1. The module checks the status of all keys in the scroller for touch contact detection.
  2. If no key is in detect, the module searches for a pair of neighboring keys whose touch delta exceeds the minimum contact threshold.
  3. If such a contact is found, then the new position is calculated.

    Or

  4. If no such contact is found, the scroller returns to ‘No Detect’ condition. That is the flag “TOUCH_ACTIVE” is cleared.