revise delay() for #114

Author: feilipu

library.properties

@@ -1,5 +1,5 @@
 name=FreeRTOS
-version=10.4.6-3
+version=10.4.6-4
 author=Richard Barry <[email protected]>
 maintainer=Phillip Stevens <[email protected]>
 sentence=<h3>FreeRTOS Real Time Operating System implemented for AVR (Uno, Nano, Leonardo, Mega).</h3>

readme.md

@@ -36,9 +36,9 @@ Watchdog period options:
 * `WDTO_1S`
 * `WDTO_2S`
 
-Note that Timer resolution is affected by integer math division and the time slice selected. Trying to measure 50ms, using a 120ms time slice for example, won't work. Also, trying to delay for less than 15ms, with the default time slice, will not work.
+Note that Timer resolution (or granularity) is affected by integer math division and the time slice selected. Trying to measure 50ms, using a 120ms time slice for example, won't work.
 
-The Arduino `delay()` function has been defined to automatically use the FreeRTOS `vTaskDelay()` function, so that simple Arduino example sketches and tutorials work with no change. If you would like to measure a short millisecond delay of less than one Tick (Watchdog period), then use [`millis()`](https://www.arduino.cc/reference/en/language/functions/time/millis/) (or with greater granularity use [`micros()`](https://www.arduino.cc/reference/en/language/functions/time/micros/)) to achieve this outcome (for example see [BlinkWithoutDelay](https://docs.arduino.cc/built-in-examples/digital/BlinkWithoutDelay)).
+The Arduino `delay()` function has been redefined to automatically use the FreeRTOS `vTaskDelay()` function when the delay required is one Tick or longer, so that simple Arduino example sketches and tutorials work as expected. If you would like to measure a short millisecond delay of less than one Tick, then preferably use [`millis()`](https://www.arduino.cc/reference/en/language/functions/time/millis/) (or with greater granularity use [`micros()`](https://www.arduino.cc/reference/en/language/functions/time/micros/)) to achieve this outcome (for example see [BlinkWithoutDelay](https://docs.arduino.cc/built-in-examples/digital/BlinkWithoutDelay)). However, when the delay requested is less than one Tick then the original Arduino `delay()` function will be automatically selected.
 
 The 8-bit AVR Timer0 has been added as an option for the experienced user. Please examine the source code to figure out how to use it. Reconfiguring Timer0 for FreeRTOS will break Arduino `millis()` and `micros()` though, as these functions rely on Timer0.
 

src/FreeRTOSVariant.h

@@ -49,7 +49,8 @@ extern "C" {
                                 WDTO_1S
                                 WDTO_2S
 */
-//    xxx Watchdog Timer is 128kHz nominal, but 120 kHz at 5V DC and 25 degrees is actually more accurate, from data sheet.
+
+/* Watchdog Timer is 128kHz nominal, but 120 kHz at 5V DC and 25 degrees is actually more accurate, from data sheet. */
 #define configTICK_RATE_HZ  ( (TickType_t)( (uint32_t)128000 >> (portUSE_WDTO + 11) ) )  // 2^11 = 2048 WDT scaler for 128kHz Timer
 
 /*-----------------------------------------------------------*/

src/mpu_wrappers.h

@@ -163,15 +163,15 @@
  * macro so applications can place data in privileged access sections
  * (useful when using statically allocated objects). */
         #define PRIVILEGED_FUNCTION
-        #define PRIVILEGED_DATA    __attribute__( ( section( "privileged_data" ) ) )
+        #define PRIVILEGED_DATA    __attribute__ ((section( "privileged_data" )))
         #define FREERTOS_SYSTEM_CALL
 
     #else /* MPU_WRAPPERS_INCLUDED_FROM_API_FILE */
 
 /* Ensure API functions go in the privileged execution section. */
-        #define PRIVILEGED_FUNCTION     __attribute__( ( section( "privileged_functions" ) ) )
-        #define PRIVILEGED_DATA         __attribute__( ( section( "privileged_data" ) ) )
-        #define FREERTOS_SYSTEM_CALL    __attribute__( ( section( "freertos_system_calls" ) ) )
+        #define PRIVILEGED_FUNCTION     __attribute__ ((section( "privileged_functions" )))
+        #define PRIVILEGED_DATA         __attribute__ ((section( "privileged_data" )))
+        #define FREERTOS_SYSTEM_CALL    __attribute__ ((section( "freertos_system_calls" )))
 
     #endif /* MPU_WRAPPERS_INCLUDED_FROM_API_FILE */
 

src/port.c

@@ -629,18 +629,41 @@ BaseType_t xPortStartScheduler( void )
 
 void vPortEndScheduler( void )
 {
-	/* It is unlikely that the ATmega port will get stopped.  If required simply
+    /* It is unlikely that the ATmega port will get stopped.  If required simply
      * disable the tick interrupt here. */
 
     wdt_disable();      /* disable Watchdog Timer */
 }
 /*-----------------------------------------------------------*/
 
-/*
- * Manual context switch. The first thing we do is save the registers so we
- * can use a naked attribute.
- */
-void vPortYield( void ) __attribute__ ( ( hot, flatten, naked ) );
+    /*
+     * Choose which delay function to use.
+     * Arduino delay() is a millisecond granularity busy wait, that
+     * that breaks FreeRTOS. So its use is limited to less than one
+     * System Tick (portTICK_PERIOD_MS milliseconds).
+     * FreeRTOS vTaskDelay() is relies on the System Tick which here
+     * has a granularity of portTICK_PERIOD_MS milliseconds (15ms).
+     */
+
+#ifdef delay
+#undef delay
+#endif
+
+void vPortDelay( const uint32_t ms ) __attribute__ ((hot, flatten));
+void vPortDelay( const uint32_t ms )
+{
+    if ( ms < portTICK_PERIOD_MS )
+        delay( ms );
+    else
+        vTaskDelay( (TickType_t) (ms) / portTICK_PERIOD_MS );
+}
+/*-----------------------------------------------------------*/
+
+    /*
+     * Manual context switch. The first thing we do is save the registers so we
+     * can use a naked attribute.
+     */
+void vPortYield( void ) __attribute__ ((hot, flatten, naked));
 void vPortYield( void )
 {
     portSAVE_CONTEXT();
@@ -651,12 +674,12 @@ void vPortYield( void )
 }
 /*-----------------------------------------------------------*/
 
-/*
- * Manual context switch callable from ISRs. The first thing we do is save
- * the registers so we can use a naked attribute.
- */
-void vPortYieldFromISR(void) __attribute__ ( ( hot, flatten, naked ) );
-void vPortYieldFromISR(void)
+    /*
+     * Manual context switch callable from ISRs. The first thing we do is save
+     * the registers so we can use a naked attribute.
+     */
+void vPortYieldFromISR( void ) __attribute__ ((hot, flatten, naked));
+void vPortYieldFromISR( void )
 {
     portSAVE_CONTEXT();
     vTaskSwitchContext();
@@ -666,13 +689,13 @@ void vPortYieldFromISR(void)
 }
 /*-----------------------------------------------------------*/
 
-/*
- * Context switch function used by the tick. This must be identical to
- * vPortYield() from the call to vTaskSwitchContext() onwards. The only
- * difference from vPortYield() is the tick count is incremented as the
- * call comes from the tick ISR.
- */
-void vPortYieldFromTick( void ) __attribute__ ( ( hot, flatten, naked ) );
+    /*
+     * Context switch function used by the tick. This must be identical to
+     * vPortYield() from the call to vTaskSwitchContext() onwards. The only
+     * difference from vPortYield() is the tick count is incremented as the
+     * call comes from the tick ISR.
+     */
+void vPortYieldFromTick( void ) __attribute__ ((hot, flatten, naked));
 void vPortYieldFromTick( void )
 {
     portSAVE_CONTEXT();
@@ -688,9 +711,9 @@ void vPortYieldFromTick( void )
 /*-----------------------------------------------------------*/
 
 #if defined(portUSE_WDTO)
-/*
- * Setup WDT to generate a tick interrupt.
- */
+    /*
+     * Setup WDT to generate a tick interrupt.
+     */
 void prvSetupTimerInterrupt( void )
 {
     /* reset watchdog */
@@ -701,9 +724,9 @@ void prvSetupTimerInterrupt( void )
 }
 
 #elif defined (portUSE_TIMER0)
-/*
- * Setup Timer0 compare match A to generate a tick interrupt.
- */
+    /*
+     * Setup Timer0 compare match A to generate a tick interrupt.
+     */
 static void prvSetupTimerInterrupt( void )
 {
 uint32_t ulCompareMatch;

src/portable.h

@@ -54,23 +54,23 @@
 #endif
 
 #if portBYTE_ALIGNMENT == 32
-    #define portBYTE_ALIGNMENT_MASK    ( 0x001f )
+    #define portBYTE_ALIGNMENT_MASK     ( 0x001f )
 #elif portBYTE_ALIGNMENT == 16
-    #define portBYTE_ALIGNMENT_MASK    ( 0x000f )
+    #define portBYTE_ALIGNMENT_MASK     ( 0x000f )
 #elif portBYTE_ALIGNMENT == 8
-    #define portBYTE_ALIGNMENT_MASK    ( 0x0007 )
+    #define portBYTE_ALIGNMENT_MASK     ( 0x0007 )
 #elif portBYTE_ALIGNMENT == 4
-    #define portBYTE_ALIGNMENT_MASK    ( 0x0003 )
+    #define portBYTE_ALIGNMENT_MASK     ( 0x0003 )
 #elif portBYTE_ALIGNMENT == 2
-    #define portBYTE_ALIGNMENT_MASK    ( 0x0001 )
+    #define portBYTE_ALIGNMENT_MASK     ( 0x0001 )
 #elif portBYTE_ALIGNMENT == 1
-    #define portBYTE_ALIGNMENT_MASK    ( 0x0000 )
+    #define portBYTE_ALIGNMENT_MASK     ( 0x0000 )
 #else /* if portBYTE_ALIGNMENT == 32 */
     #error "Invalid portBYTE_ALIGNMENT definition"
 #endif /* if portBYTE_ALIGNMENT == 32 */
 
 #ifndef portUSING_MPU_WRAPPERS
-    #define portUSING_MPU_WRAPPERS    0
+    #define portUSING_MPU_WRAPPERS      0
 #endif
 
 #ifndef portNUM_CONFIGURABLE_REGIONS
@@ -82,7 +82,16 @@
 #endif
 
 #ifndef portARCH_NAME
-    #define portARCH_NAME    NULL
+    #define portARCH_NAME               NULL
+#endif
+
+/*
+ * Delay is implemented as either Arduino delay() if the delay is less than one Tick,
+ * or otherwise FreeRTOS vTaskDelay().
+ *
+ */
+#ifndef delay
+#define delay                           vPortDelay
 #endif
 
 #ifndef configSTACK_ALLOCATION_FROM_SEPARATE_HEAP

src/portmacro.h

@@ -96,18 +96,20 @@ typedef uint8_t                     UBaseType_t;
 #define portTICK_PERIOD_MS          ( (TickType_t) 1000 / configTICK_RATE_HZ )
 #endif
 
-#define delay(ms)                   vTaskDelay((TickType_t)(ms)/portTICK_PERIOD_MS)
-
 #define portBYTE_ALIGNMENT          1
 #define portNOP()                   __asm__ __volatile__ ( "nop" );
 /*-----------------------------------------------------------*/
 
 /* Kernel utilities. */
-extern void vPortYield( void )      __attribute__ ( ( naked ) );
+
+extern void vPortDelay( const uint32_t ms );
+#define portDELAY( ms )             vPortDelay( ms )
+
+extern void vPortYield( void );
 #define portYIELD()                 vPortYield()
 
-extern void vPortYieldFromISR( void )   __attribute__ ( ( naked ) );
-#define portYIELD_FROM_ISR()            vPortYieldFromISR()
+extern void vPortYieldFromISR( void );
+#define portYIELD_FROM_ISR()        vPortYieldFromISR()
 /*-----------------------------------------------------------*/
 
 #if defined(__AVR_3_BYTE_PC__)

src/tasks.c

@@ -333,7 +333,7 @@ typedef struct TaskControlBlock_t
 
 /*lint -save -e956 A manual analysis and inspection has been used to determine
  * which static variables must be declared volatile. */
-PRIVILEGED_DATA TCB_t * volatile pxCurrentTCB __attribute__((used)) = NULL;
+PRIVILEGED_DATA TCB_t * volatile pxCurrentTCB __attribute__ ((used)) = NULL;
 
 /* Lists for ready and blocked tasks. --------------------
  * xDelayedTaskList1 and xDelayedTaskList2 could be moved to function scope but

src/variantHooks.cpp

@@ -43,6 +43,7 @@ extern void loop(void);
 /*-----------------------------------------------------------*/
 
 void initVariant(void) __attribute__ ((OS_main));
+
 void initVariant(void)
 {
     // As the Task stacks are on heap before Task allocated heap variables,
@@ -68,7 +69,7 @@ void initVariant(void)
  * NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES, CALL A FUNCTION THAT MIGHT BLOCK.
  *
  */
-void vApplicationIdleHook( void ) __attribute__((weak));
+void vApplicationIdleHook( void ) __attribute__ ((weak));
 
 void vApplicationIdleHook( void )
 {
@@ -149,7 +150,7 @@ void prvBlinkMainLed( void )
     This routine will never return.
     This routine is referenced in the task.c file of FreeRTOS as an extern.
 \*---------------------------------------------------------------------------*/
-void vApplicationMallocFailedHook( void ) __attribute__((weak));
+void vApplicationMallocFailedHook( void ) __attribute__ ((weak));
 
 void vApplicationMallocFailedHook( void )
 {
@@ -169,10 +170,10 @@ void vApplicationMallocFailedHook( void )
 #if ( configCHECK_FOR_STACK_OVERFLOW >= 1 )
 
 void vApplicationStackOverflowHook( TaskHandle_t xTask,
-                                    char * pcTaskName ) __attribute__((weak));
+                                    char * pcTaskName ) __attribute__ ((weak));
 
-void vApplicationStackOverflowHook( TaskHandle_t xTask __attribute__((unused)),
-                                    char * pcTaskName __attribute__((unused)) )
+void vApplicationStackOverflowHook( TaskHandle_t xTask __attribute__ ((unused)),
+                                    char * pcTaskName __attribute__ ((unused)) )
 {
 
     prvSetMainLedOn(); // Main LED on.
@@ -191,7 +192,7 @@ void vApplicationStackOverflowHook( TaskHandle_t xTask __attribute__((unused)),
 
 void vApplicationGetIdleTaskMemory( StaticTask_t ** ppxIdleTaskTCBBuffer,
                                     StackType_t ** ppxIdleTaskStackBuffer,
-                                    configSTACK_DEPTH_TYPE * pulIdleTaskStackSize ) __attribute__((weak));
+                                    configSTACK_DEPTH_TYPE * pulIdleTaskStackSize ) __attribute__ ((weak));
 
 void vApplicationGetIdleTaskMemory( StaticTask_t ** ppxIdleTaskTCBBuffer,
                                     StackType_t ** ppxIdleTaskStackBuffer,
@@ -209,7 +210,7 @@ void vApplicationGetIdleTaskMemory( StaticTask_t ** ppxIdleTaskTCBBuffer,
 
 void vApplicationGetTimerTaskMemory( StaticTask_t ** ppxTimerTaskTCBBuffer,
                                      StackType_t ** ppxTimerTaskStackBuffer,
-                                     configSTACK_DEPTH_TYPE * pulTimerTaskStackSize ) __attribute__((weak));
+                                     configSTACK_DEPTH_TYPE * pulTimerTaskStackSize ) __attribute__ ((weak));
 
 void vApplicationGetTimerTaskMemory( StaticTask_t ** ppxTimerTaskTCBBuffer,
                                      StackType_t ** ppxTimerTaskStackBuffer,