Synopsis

CTL_STATUS_t platform_hook_pin_edge(int pin,
                                    PLATFORM_EDGE_t edge,
                                    PLATFORM_HOOK_t *hook);

Description

platform_hook_pin_edge hooks the function hook so that it is activated by an edge on pin pin. The edge parameter requests that the hook be triggered on a rising edge, a falling edge, or either edge.

The activated hook is executed in an interrupt context, not a task context, and without any surrounding calls to ctl_enter_isr and ctl_exit_isr. If your hook requires CTL facilities, you must ensure that you call ctl_enter_isr and ctl_exit_isr as you would in a standard CTL interrupt handler.

Return Value

platform_hook_pin_edge returns a standard status code. Hooking an interrupt is inherently platform-dependent and may fail for any of the following reasons:

• A hook is already established for the pin. Some platforms may support more than one hook per pin and chain them, whereas others may support exactly one hook per pin. It is typically not possible to establish distinct hooks for rising and falling edges of a pin, but the platform supports a single hook for both edges.
• The platform is out of resources when associating interrupts with pins. For instance, STM32 devices can hook an interrupt to bits 0 through 31 of any port, but cannot simultaneously establish hooks for the same bit on different ports, i.e. you cannot establish hooks for interrupts on both PORTA[4] and PORTC[4] as they share the same internal resource, but you can establish hooks for PORTA[4] and PORTC[5] as they use different pins.
• The port pin cannot generate interrupts.
• The port pin does not support the requested edge trigger.

See Also

PLATFORM_HOOK_t, PLATFORM_EDGE_t