Edge detection

Informative

How to detect pin edges and handle the events. Binding rules: CHI-PORT-MUST-07, CHI-PORT-MUST-08, and CHI-PORT-MUST-09 in Port — Requirements.

Enable edge detection

Port_Init leaves edge detection off on every pin. Enable it per pin with the edge type you want:

Port_SetEdgeDetection(PORT_PIN_BUTTON, PORT_EDGE_CONFIG_RISING);   /* NONE/RISING/FALLING/BOTH */

To turn detection back off, set PORT_EDGE_CONFIG_NONE.

Handle the event

When a configured edge occurs, the driver calls the Port_Callout_OnEdgeDetection callout with the pin id. Fill in its user code block in Port_Callout_Stubs.c (see The Callout Stub File):

void Port_Callout_OnEdgeDetection(uint16 pinId)
{
    if (pinId == PORT_PIN_BUTTON) {
        /* the button edge fired */
    }
}

The callout runs from whichever service handles the event for that pin:

• Interrupt pins — the event is serviced in Port_Interrupt (define it with the ISR() macro; see the general reference).

• Polling pins — call Port_PollFunction cyclically; it services the same events.

Note

The event-handling mode is set per pin in the configuration (event_handling_mode: Interrupt | Polling). A PORT_EDGE_CONFIG_* value the hardware does not support raises PORT_DEVERR_PARAM_EDGE_CONFIG (Errors).