/* | |
FreeRTOS V8.0.1 - Copyright (C) 2014 Real Time Engineers Ltd. | |
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*/ | |
/* **************************************************************************** | |
* When configCREATE_LOW_POWER_DEMO is set to 1 in FreeRTOSConfig.h main() will | |
* call main_low_power(), which is defined in this file. main_low_power() | |
* demonstrates FreeRTOS tick suppression being used to allow the MCU to be | |
* placed into both the low power deep sleep mode and the low power software | |
* standby mode. When configCREATE_LOW_POWER_DEMO is set to 0 main will | |
* instead call main_full(), which is a more comprehensive RTOS demonstration. | |
* **************************************************************************** | |
* | |
* This application demonstrates the FreeRTOS tickless idle mode (tick | |
* suppression). See http://www.freertos.org/low-power-tickless-rtos.html | |
* The demo is configured to execute on the Renesas RX100 RSK. | |
* | |
* Functionality: | |
* | |
* + Two tasks are created, an Rx task and a Tx task. | |
* | |
* + The Rx task repeatedly blocks on a queue to wait for data. The Rx task | |
* toggles LED 0 each time is receives a value from the queue. | |
* | |
* + The Tx task repeatedly enters the Blocked state for an amount of time | |
* that is set by the position of the potentiometer. On exiting the blocked | |
* state the Tx task sends a value through the queue to the Rx task (causing | |
* the Rx task to exit the blocked state and toggle LED 0). | |
* | |
* If the value read from the potentiometer is less than or equal to | |
* mainSOFTWARE_STANDBY_DELAY then the Tx task blocks for the equivalent | |
* number of milliseconds. For example, if the sampled analog value is | |
* 2000, then the Tx task blocks for 2000ms. Blocking for a finite period | |
* allows the kernel to stop the tick interrupt and place the RX100 into | |
* deep sleep mode. | |
* | |
* If the value read form the potentiometer is greater than | |
* mainSOFTWARE_STANDBY_DELAY then the Tx task blocks on a semaphore with | |
* an infinite timeout. Blocking with an infinite timeout allows the kernel | |
* to stop the tick interrupt and place the RX100 into software standby | |
* mode. Pressing a button will generate an interrupt that causes the RX100 | |
* to exit software standby mode. The interrupt service routine 'gives' the | |
* semaphore to unblock the Tx task. | |
* | |
* | |
* Using the Demo and Observed Behaviour: | |
* | |
* 1) Turn the potentiometer completely counter clockwise. | |
* | |
* 2) Program the RX100 with the application, then disconnect the programming/ | |
* debugging hardware to ensure power readings are not effected by any | |
* connected interfaces. | |
* | |
* 3) Start the application running. LED 0 will toggle quickly because the | |
* potentiometer is turned to its lowest value. LED 1 will be illuminated | |
* when the RX100 is not in a power saving mode, but will appear to be off | |
* because most execution time is spent in a sleep mode. Led 2 will be | |
* illuminated when the RX100 is in deep sleep mode, and will appear to be | |
* always on, again because most execution time is spent in deep sleep mode. | |
* The LEDs are turned on and off by the application defined pre and post | |
* sleep macros (see the definitions of configPRE_SLEEP_PROCESSING() and | |
* configPOST_SLEEP_PROCESSING() in FreeRTOSConfig.h). | |
* | |
* 4) Slowly turn the potentiometer in the clockwise direction. This will | |
* increase the value read from the potentiometer, which will increase the | |
* time the Tx task spends in the Blocked state, which will therefore | |
* decrease the frequency at which the Tx task sends data to the queue (and | |
* the rate at which LED 0 is toggled). | |
* | |
* 5) Keep turning the potentiometer in the clockwise direction. Eventually | |
* the value read from the potentiometer will go above | |
* mainSOFTWARE_STANDBY_DELAY, causing the Tx task to block on the semaphore | |
* with an infinite timeout. LED 0 will stop toggling because the Tx task is | |
* no longer sending to the queue. LED 1 and LED 2 will both be off because | |
* the RX100 is neither running or in deep sleep mode (it is in software | |
* standby mode). | |
* | |
* 6) Turn the potentiometer counter clockwise again to ensure its value goes | |
* back below mainSOFTWARE_STANDBY_DELAY. | |
* | |
* 7) Press any of the three buttons to generate an interrupt. The interrupt | |
* will take the RX100 out of software standby mode, and the interrupt | |
* service routine will unblock the Tx task by 'giving' the semaphore. LED 0 | |
* will then start to toggle again. | |
* | |
*/ | |
/* Hardware specific includes. */ | |
#include "platform.h" | |
#include "r_switches_if.h" | |
/* Kernel includes. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
#include "queue.h" | |
#include "semphr.h" | |
/* Common demo includes. */ | |
#include "partest.h" | |
/* Priorities at which the Rx and Tx tasks are created. */ | |
#define configQUEUE_RECEIVE_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 ) | |
#define configQUEUE_SEND_TASK_PRIORITY ( tskIDLE_PRIORITY + 2 ) | |
/* The number of items the queue can hold. This is 1 as the Rx task will | |
remove items as they are added so the Tx task should always find the queue | |
empty. */ | |
#define mainQUEUE_LENGTH ( 1 ) | |
/* The LED used to indicate that a value has been received on the queue. */ | |
#define mainQUEUE_LED ( 0 ) | |
/* The LED used to indicate that full power is being used (the MCU is not in | |
deep sleep or software standby mode). */ | |
#define mainFULL_POWER_LED ( 1 ) | |
/* The LED used to indicate that deep sleep mode is being used. */ | |
#define mainDEEP_SLEEP_LED ( 2 ) | |
/* The Tx task sends to the queue with a frequency that is set by the value | |
read from the potentiometer until the value goes above that set by the | |
mainSOFTWARE_STANDBY_DELAY constant - at which time the Tx task instead blocks | |
indefinitely on a semaphore. */ | |
#define mainSOFTWARE_STANDBY_DELAY ( 3000UL ) | |
/* A block time of zero simply means "don't block". */ | |
#define mainDONT_BLOCK ( 0 ) | |
/* The value that is sent from the Tx task to the Rx task on the queue. */ | |
#define mainQUEUED_VALUE ( 100UL ) | |
/*-----------------------------------------------------------*/ | |
/* | |
* The Rx and Tx tasks as described at the top of this file. | |
*/ | |
static void prvQueueReceiveTask( void *pvParameters ); | |
static void prvQueueSendTask( void *pvParameters ); | |
/* | |
* Reads and returns the value of the ADC connected to the potentiometer built | |
* onto the RSK. | |
*/ | |
static unsigned short prvReadPOT( void ); | |
/* | |
* The handler for the interrupt generated when any of the buttons are pressed. | |
*/ | |
__interrupt void vButtonInterrupt( void ); | |
/*-----------------------------------------------------------*/ | |
/* The queue to pass data from the Tx task to the Rx task. */ | |
static QueueHandle_t xQueue = NULL; | |
/* The semaphore that is 'given' by interrupts generated from button pushes. */ | |
static SemaphoreHandle_t xSemaphore = NULL; | |
/*-----------------------------------------------------------*/ | |
void main_low_power( void ) | |
{ | |
/* Create the queue. */ | |
xQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( unsigned long ) ); | |
configASSERT( xQueue ); | |
/* Create the semaphore that is 'given' by an interrupt generated from a | |
button push. */ | |
vSemaphoreCreateBinary( xSemaphore ); | |
configASSERT( xSemaphore ); | |
/* Make sure the semaphore starts in the expected state - no button pushes | |
have yet occurred. A block time of zero can be used as it is guaranteed | |
that the semaphore will be available because it has just been created. */ | |
xSemaphoreTake( xSemaphore, mainDONT_BLOCK ); | |
/* Start the two tasks as described at the top of this file. */ | |
xTaskCreate( prvQueueReceiveTask, "Rx", configMINIMAL_STACK_SIZE, NULL, configQUEUE_RECEIVE_TASK_PRIORITY, NULL ); | |
xTaskCreate( prvQueueSendTask, "TX", configMINIMAL_STACK_SIZE, NULL, configQUEUE_SEND_TASK_PRIORITY, NULL ); | |
/* The CPU is currently running, not sleeping, so turn on the LED that | |
shows the CPU is not in a sleep mode. */ | |
vParTestSetLED( mainFULL_POWER_LED, pdTRUE ); | |
/* Start the scheduler running running. */ | |
vTaskStartScheduler(); | |
/* If all is well the next line of code will not be reached as the | |
scheduler will be running. If the next line is reached then it is likely | |
there was insufficient FreeRTOS heap available for the idle task and/or | |
timer task to be created. See http://www.freertos.org/a00111.html. */ | |
for( ;; ); | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvQueueSendTask( void *pvParameters ) | |
{ | |
TickType_t xDelay; | |
const unsigned long ulValueToSend = mainQUEUED_VALUE; | |
/* Remove compiler warning about unused parameter. */ | |
( void ) pvParameters; | |
for( ;; ) | |
{ | |
/* The delay period between successive sends to the queue is set by | |
the potentiometer reading. */ | |
xDelay = ( TickType_t ) prvReadPOT(); | |
/* If the block time is greater than 3000 milliseconds then block | |
indefinitely waiting for a button push. */ | |
if( xDelay > mainSOFTWARE_STANDBY_DELAY ) | |
{ | |
/* As this is an indefinite delay the kernel will place the CPU | |
into software standby mode the next time the idle task runs. */ | |
xSemaphoreTake( xSemaphore, portMAX_DELAY ); | |
} | |
else | |
{ | |
/* Convert a time in milliseconds to a time in ticks. */ | |
xDelay /= portTICK_PERIOD_MS; | |
/* Place this task in the blocked state until it is time to run | |
again. As this is not an indefinite sleep the kernel will place | |
the CPU into the deep sleep state when the idle task next runs. */ | |
vTaskDelay( xDelay ); | |
} | |
/* Send to the queue - causing the queue receive task to flash its LED. | |
It should not be necessary to block on the queue send because the Rx | |
task will have removed the last queued item. */ | |
xQueueSend( xQueue, &ulValueToSend, mainDONT_BLOCK ); | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvQueueReceiveTask( void *pvParameters ) | |
{ | |
unsigned long ulReceivedValue; | |
/* Remove compiler warning about unused parameter. */ | |
( void ) pvParameters; | |
for( ;; ) | |
{ | |
/* Wait until something arrives in the queue - this will block | |
indefinitely provided INCLUDE_vTaskSuspend is set to 1 in | |
FreeRTOSConfig.h. */ | |
xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY ); | |
/* To get here something must have arrived, but is it the expected | |
value? If it is, toggle the LED. */ | |
if( ulReceivedValue == mainQUEUED_VALUE ) | |
{ | |
vParTestToggleLED( mainQUEUE_LED ); | |
} | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
void vPreSleepProcessing( unsigned long ulExpectedIdleTime ) | |
{ | |
/* Called by the kernel before it places the MCU into a sleep mode because | |
configPRE_SLEEP_PROCESSING() is #defined to vPreSleepProcessing(). | |
NOTE: Additional actions can be taken here to get the power consumption | |
even lower. For example, the ADC input used by this demo could be turned | |
off here, and then back on again in the post sleep processing function. | |
For maximum power saving ensure all unused pins are in their lowest power | |
state. */ | |
/* Avoid compiler warnings about the unused parameter. */ | |
( void ) ulExpectedIdleTime; | |
/* Is the MCU about to enter deep sleep mode or software standby mode? */ | |
if( SYSTEM.SBYCR.BIT.SSBY == 0 ) | |
{ | |
/* Turn on the LED that indicates deep sleep mode is being entered. */ | |
vParTestSetLED( mainDEEP_SLEEP_LED, pdTRUE ); | |
} | |
else | |
{ | |
/* Software standby mode is being used, so no LEDs are illuminated to | |
ensure minimum power readings are obtained. Ensure the Queue LED is | |
also off. */ | |
vParTestSetLED( mainQUEUE_LED, pdFALSE ); | |
} | |
/* Turn off the LED that indicates full power is being used. */ | |
vParTestSetLED( mainFULL_POWER_LED, pdFALSE ); | |
} | |
/*-----------------------------------------------------------*/ | |
void vPostSleepProcessing( unsigned long ulExpectedIdleTime ) | |
{ | |
/* Called by the kernel when the MCU exits a sleep mode because | |
configPOST_SLEEP_PROCESSING is #defined to vPostSleepProcessing(). */ | |
/* Avoid compiler warnings about the unused parameter. */ | |
( void ) ulExpectedIdleTime; | |
/* Turn off the LED that indicates deep sleep mode, and turn on the LED | |
that indicates full power is being used. */ | |
vParTestSetLED( mainDEEP_SLEEP_LED, pdFALSE ); | |
vParTestSetLED( mainFULL_POWER_LED, pdTRUE ); | |
} | |
/*-----------------------------------------------------------*/ | |
static unsigned short prvReadPOT( void ) | |
{ | |
unsigned short usADCValue; | |
const unsigned short usMinADCValue = 128; | |
/* Start an ADC scan. */ | |
S12AD.ADCSR.BIT.ADST = 1; | |
while( S12AD.ADCSR.BIT.ADST == 1 ) | |
{ | |
/* Just waiting for the ADC scan to complete. Inefficient | |
polling! */ | |
} | |
usADCValue = S12AD.ADDR4; | |
/* Don't let the ADC value get too small as the LED behaviour will look | |
erratic. */ | |
if( usADCValue < usMinADCValue ) | |
{ | |
usADCValue = usMinADCValue; | |
} | |
return usADCValue; | |
} | |
/*-----------------------------------------------------------*/ | |
#pragma vector = VECT_ICU_IRQ0, VECT_ICU_IRQ1, VECT_ICU_IRQ4 | |
__interrupt void vButtonInterrupt1( void ) | |
{ | |
long lHigherPriorityTaskWoken = pdFALSE; | |
/* The semaphore is only created when the build is configured to create the | |
low power demo. */ | |
if( xSemaphore != NULL ) | |
{ | |
/* This interrupt will bring the CPU out of deep sleep and software | |
standby modes. Give the semaphore that was used to place the Tx task | |
into an indefinite sleep. */ | |
if( uxQueueMessagesWaitingFromISR( xSemaphore ) == 0 ) | |
{ | |
xSemaphoreGiveFromISR( xSemaphore, &lHigherPriorityTaskWoken ); | |
} | |
else | |
{ | |
/* The semaphore was already available, so the task is not blocked | |
on it and there is no point giving it. */ | |
} | |
/* If giving the semaphore caused a task to leave the Blocked state, | |
and the task that left the Blocked state has a priority equal to or | |
above the priority of the task that this interrupt interrupted, then | |
lHigherPriorityTaskWoken will have been set to pdTRUE inside the call | |
to xSemaphoreGiveFromISR(), and calling portYIELD_FROM_ISR() will cause | |
a context switch to the unblocked task. */ | |
portYIELD_FROM_ISR( lHigherPriorityTaskWoken ); | |
} | |
} | |