Core that handles touch sensor events and provides them to the SW via an API.
This core implements a touch sensor handler. The core detects and holds events for SW to read. The touch sensor input is expected to be a change in level from low (0) to high (1). When an event is seen, the core will set a status bit that SW can read.
SW must clear the captured event by writing to the status register. The core will wait for the sensor input to become low again before being able to detect another event.
The API has two addresses.
ADDR_STATUS: 0x09
STATUS_EVENT_BIT: 0
ADDR_PRESENT: 0x0a
FINGER_PRESENT_BIT: 0
In order to detect an event, SW should clear any stray attempts before signalling to the user that a touch event is expected. Clearing an event is done by writing the the status address, the value written does not matter.
When an event has been detected, that is the sampled input from the sensor has gone from low to high, the STATUS_EVENT_BIT will be high (set). When SW reads a high bit, the SW should as soon as possible clear the event by writing to the status register. The value written does not matter.
The FINGER_PRESENT bit is the sampled input from the sensor. The bit will be high as long as a finger is present on the sensor. When a finger is present the bit will be low.