AN3299

Software

Doc ID 18113 Rev 1

11/13

2.2.2

Interrupt handling

The following is a sample for the device interrupt/hotkey serving routine based on standard

implementation.

●

Interrupt service routine

ON_INTERRUPT

GPIO_INT_STATUS = ReadRegister(INT_STA_GPIO); //Read Interrupt

Status register - Is cleared on read.

If((GPIO_INT_STATUS & 0x80) == 0x80) // Check for interrupt on GPIO7

{

// Handle GPIO interrupt

}

2.3

Hotkey de-bounce

It is possible that a signal from a mechanical connector (e.g. a 3.5 mm earphone jack) is

connected to the STMPE801 input as a hotkey input. In such a case, excessive noise is

expected from the hotkey input due to the mechanical movement, which the STMPE801 is

not equipped to filter. It is necessary that the host implements filtering or de-bouncing by

polling the status bit in the Interrupt status register (0x09).