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ESP32 and RTOS Tasks
Drzony edited this page Aug 6, 2021
·
1 revision
On ESP32, when the CPU is loaded, asynchronous WiFi libraries (like ESPAsyncWebServer or async-mqtt-client) may interfere with interrupts used to control the LEDs (I2S mode is less affected by this), which causes flickering of LEDs.
One way to solve that is to create a high priority task that will take care of showing the LEDs.
The following code is an example of this approach:
xSemaphoreHandle semaphore = NULL;
TaskHandle_t commit_task;
NeoPixelBus<NeoGrbFeature, NeoEsp32RmtNWs2811Method> pixel_bus;
void commitTaskProcedure(void *arg)
{
while (true)
{
while (ulTaskNotifyTake(pdTRUE, portMAX_DELAY) != 1)
;
pixel_bus.Show();
while (!pixel_bus.CanShow())
;
xSemaphoreGive(semaphore);
}
}
void commit()
{
xTaskNotifyGive(commit_task);
while (xSemaphoreTake(semaphore, portMAX_DELAY) != pdTRUE)
;
}
void init_task()
{
commit_task = NULL;
semaphore = xSemaphoreCreateBinary();
xTaskCreatePinnedToCore(
commitTaskProcedure, /* Task function. */
"ShowRunnerTask", /* name of task. */
10000, /* Stack size of task */
NULL, /* parameter of the task */
4, /* priority of the task */
&commit_task, /* Task handle to keep track of created task */
1); /* pin task to core core_id */
}
void setup()
{
pixel_bus.begin();
init_task();
}
void loop()
{
commit();
delay(10);
}