Enabled static memory allocation with example (#842)

Co-authored-by: Dario Gogliandolo <dario.gogliandolo@smartme.io>

libraries/FreeRTOS/examples/StaticMulticore-FreeRTOS/StaticMulticore-FreeRTOS.ino

+/* The code in this example is mostly derived from the official FreeRTOS
+ * code examples.
+ * 
+ * For more information on static allocation and to read the original
+ * code visit the following links:
+ * https://www.freertos.org/Static_Vs_Dynamic_Memory_Allocation.html
+ * https://www.freertos.org/xTaskCreateStatic.html
+ * https://www.freertos.org/xSemaphoreCreateMutexStatic.html
+ */
+
+#include <FreeRTOS.h>
+#include <task.h>
+#include <semphr.h>
+
+#define SERIAL_PORT Serial1
+#define BLINK_ON_TIME   250
+#define BLINK_OFF_TIME  500
+
+/* Dimensions of the buffer that the task being created will use as its stack.
+  NOTE:  This is the number of words the stack will hold, not the number of
+  bytes.  For example, if each stack item is 32-bits, and this is set to 100,
+  then 400 bytes (100 * 32-bits) will be allocated. */
+#define STACK_SIZE 200
+
+/* Structure that will hold the TCB of the task being created. */
+StaticTask_t xTaskBuffer_A;
+StaticTask_t xTaskBuffer_B;
+
+/* Buffer that the task being created will use as its stack.  Note this is
+  an array of StackType_t variables.  The size of StackType_t is dependent on
+  the RTOS port. */
+StackType_t xStack_A[ STACK_SIZE ];
+StackType_t xStack_B[ STACK_SIZE ];
+
+SemaphoreHandle_t xSemaphore = NULL;
+StaticSemaphore_t xMutexBuffer;
+
+void setup() {
+  SERIAL_PORT.begin(115200);
+  pinMode(LED_BUILTIN, OUTPUT);
+
+  /* Create a mutex semaphore without using any dynamic memory
+    allocation.  The mutex's data structures will be saved into
+    the xMutexBuffer variable. */
+  xSemaphore = xSemaphoreCreateMutexStatic( &xMutexBuffer );
+
+  xTaskCreateStatic(led_ON, "led_ON", STACK_SIZE, NULL, configMAX_PRIORITIES - 1, xStack_A, &xTaskBuffer_A);
+  xTaskCreateStatic(led_OFF, "led_OFF", STACK_SIZE, NULL, configMAX_PRIORITIES - 1, xStack_B, &xTaskBuffer_B);
+}
+
+void led_ON(void *pvParameters)
+{
+  (void) pvParameters;
+  while (1)
+  {
+    xSemaphoreTake( xSemaphore, ( TickType_t ) portMAX_DELAY );
+    SERIAL_PORT.println("LED ON!");
+    digitalWrite(LED_BUILTIN, HIGH);
+    delay(BLINK_ON_TIME);
+    xSemaphoreGive( xSemaphore );
+  }
+}
+
+void led_OFF(void *pvParameters)
+{
+  (void) pvParameters;
+  while (1)
+  {
+    xSemaphoreTake( xSemaphore, ( TickType_t ) portMAX_DELAY );
+    SERIAL_PORT.println("LED OFF!");
+    digitalWrite(LED_BUILTIN, LOW);
+    delay(BLINK_OFF_TIME);
+    xSemaphoreGive( xSemaphore );
+  }
+}
+
+void loop() {
+  SERIAL_PORT.println("Hello!");
+  delay(1000);
+}

libraries/FreeRTOS/src/FreeRTOSConfig.h

@@ -24,7 +24,7 @@
 #define configUSE_COUNTING_SEMAPHORES	1
 #define configUSE_QUEUE_SETS			1
 #define configSUPPORT_DYNAMIC_ALLOCATION 1
-#define configSUPPORT_STATIC_ALLOCATION 0
+#define configSUPPORT_STATIC_ALLOCATION 1
 #define configSTACK_DEPTH_TYPE			uint32_t
 #define configUSE_TASK_PREEMPTION_DISABLE 1