Event Interface
The ADF provides the Event Interface API to establish communication between Audio Elements in a pipeline. The API is built around FreeRTOS queue. It implements ‘listeners’ to watch for incoming messages and inform about them with a callback function.
Application Examples
Implementation of this API is demonstrated in couple of examples including get-started/play_mp3_control.
API Reference
Header File
Functions
-
audio_event_iface_handle_t audio_event_iface_init(audio_event_iface_cfg_t *config)
Initialize audio event.
- 参数
config – The configurations
- 返回
ESP_OK
ESP_FAIL
-
esp_err_t audio_event_iface_destroy(audio_event_iface_handle_t evt)
Cleanup event, it doesn’t free evt pointer.
- 参数
evt – The event
- 返回
ESP_OK
ESP_FAIL
-
esp_err_t audio_event_iface_set_listener(audio_event_iface_handle_t evt, audio_event_iface_handle_t listener)
Add audio event
evt
to the listener, then we can listenevt
event fromlisten
- 参数
listener – The event can listen another event
evt – The event to be added to
- 返回
ESP_OK
ESP_FAIL
-
esp_err_t audio_event_iface_remove_listener(audio_event_iface_handle_t listener, audio_event_iface_handle_t evt)
Remove audio event
evt
from the listener.- 参数
listener – The event listener
evt – The event to be removed from
- 返回
ESP_OK
ESP_FAIL
-
esp_err_t audio_event_iface_set_cmd_waiting_timeout(audio_event_iface_handle_t evt, TickType_t wait_time)
Set current queue wait time for the event.
- 参数
evt – The event
wait_time – [in] The wait time
- 返回
ESP_OK
ESP_FAIL
-
esp_err_t audio_event_iface_waiting_cmd_msg(audio_event_iface_handle_t evt)
Waiting internal queue message.
- 参数
evt – The event
- 返回
ESP_OK
ESP_FAIL
-
esp_err_t audio_event_iface_cmd(audio_event_iface_handle_t evt, audio_event_iface_msg_t *msg)
Trigger an event for internal queue with a message.
- 参数
evt – The event
msg – The message
- 返回
ESP_OK
ESP_FAIL
-
esp_err_t audio_event_iface_cmd_from_isr(audio_event_iface_handle_t evt, audio_event_iface_msg_t *msg)
It’s same with
audio_event_iface_cmd
, but can send a message from ISR.- 参数
evt – [in] The event
msg – The message
- 返回
ESP_OK
ESP_FAIL
-
esp_err_t audio_event_iface_sendout(audio_event_iface_handle_t evt, audio_event_iface_msg_t *msg)
Trigger and event out with a message.
- 参数
evt – The event
msg – The message
- 返回
ESP_OK
ESP_FAIL
-
esp_err_t audio_event_iface_discard(audio_event_iface_handle_t evt)
Discard all ongoing event message.
- 参数
evt – The event
- 返回
ESP_OK
ESP_FAIL
-
esp_err_t audio_event_iface_listen(audio_event_iface_handle_t evt, audio_event_iface_msg_t *msg, TickType_t wait_time)
Listening and invoke callback function if there are any event are comming.
- 参数
evt – The event
msg – The message
wait_time – The wait time
- 返回
ESP_OK
ESP_FAIL
-
QueueHandle_t audio_event_iface_get_queue_handle(audio_event_iface_handle_t evt)
Get External queue handle of Emmitter.
- 参数
evt – [in] The external queue
- 返回
External QueueHandle_t
-
esp_err_t audio_event_iface_read(audio_event_iface_handle_t evt, audio_event_iface_msg_t *msg, TickType_t wait_time)
Read the event from all the registered event emitters in the queue set of the interface.
- 参数
evt – [in] The event interface
msg – [out] The pointer to structure in which event is to be received
wait_time – [in] Timeout for receiving event
- 返回
ESP_OK On successful receiving of event
ESP_FAIL In case of a timeout or invalid parameter passed
-
QueueHandle_t audio_event_iface_get_msg_queue_handle(audio_event_iface_handle_t evt)
Get Internal queue handle of Emmitter.
- 参数
evt – [in] The Internal queue
- 返回
Internal QueueHandle_t
-
esp_err_t audio_event_iface_set_msg_listener(audio_event_iface_handle_t evt, audio_event_iface_handle_t listener)
Add audio internal event
evt
to the listener, then we can listenevt
event fromlisten
- 参数
listener – The event can listen another event
evt – The event to be added to
- 返回
ESP_OK
ESP_FAIL
Structures
-
struct audio_event_iface_msg_t
Event message
-
struct audio_event_iface_cfg_t
Event interface configurations
Public Members
-
int internal_queue_size
It’s optional, Queue size for event
internal_queue
-
int external_queue_size
It’s optional, Queue size for event
external_queue
-
int queue_set_size
It’s optional, QueueSet size for event
queue_set
-
on_event_iface_func on_cmd
Function callback for listener when any event arrived
-
void *context
Context will pass to callback function
-
TickType_t wait_time
Timeout to check for event queue
-
int type
it will pass to audio_event_iface_msg_t source_type (To know where it came from)
-
int internal_queue_size
Macros
-
DEFAULT_AUDIO_EVENT_IFACE_SIZE
-
AUDIO_EVENT_IFACE_DEFAULT_CFG()
Type Definitions
-
typedef esp_err_t (*on_event_iface_func)(audio_event_iface_msg_t*, void*)
-
typedef struct audio_event_iface *audio_event_iface_handle_t