/* | |
* FreeRTOS Kernel V10.1.1 | |
* Copyright (C) 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved. | |
* | |
* Permission is hereby granted, free of charge, to any person obtaining a copy of | |
* this software and associated documentation files (the "Software"), to deal in | |
* the Software without restriction, including without limitation the rights to | |
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of | |
* the Software, and to permit persons to whom the Software is furnished to do so, | |
* subject to the following conditions: | |
* | |
* The above copyright notice and this permission notice shall be included in all | |
* copies or substantial portions of the Software. | |
* | |
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS | |
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR | |
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER | |
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. | |
* | |
* http://www.FreeRTOS.org | |
* http://aws.amazon.com/freertos | |
* | |
* 1 tab == 4 spaces! | |
*/ | |
/* **************************************************************************** | |
* 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 the Retention low power 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 SAM4L-EK. | |
* | |
* Functionality: | |
* | |
* + Two tasks are created, an Rx task and a Tx task. | |
* | |
* + The Rx task blocks on a queue to wait for data, blipping an LED each time | |
* data is received (turning it on and then off again) before returning to | |
* block on the queue once more. | |
* | |
* + The Tx task repeatedly enters the Blocked state for 500ms. 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 blip the LED). | |
* | |
* Blocking for a finite period allows the kernel to stop the tick interrupt | |
* and place the SAM4L into Retention mode - the lowest power mode possible | |
* that allows the CPU registers and RAM to retain their state. | |
* | |
* Observed behaviour: | |
* | |
* For correct results the SAM4L-EK must be connected (and powered) using only | |
* the JTAG USB connector, but the debugger must not be connected (the | |
* application must be executed 'stand alone'). | |
* | |
* The MCU spends most of its time in the Retention low power state, during | |
* which times the current monitor (built onto the SAM4L-EK) will show a low | |
* current reading. | |
* | |
* Every 500ms the MCU will come out of the low power state to turn the LED on, | |
* then return to the low power state for 20ms before leaving the low power | |
* state again to turn the LED off. This will be observed as a fast blipping | |
* on the LED, and two very brief dots appearing on the current monitor graph | |
* (often observed as a single dot). | |
* | |
* The RTOS tick is suppressed while the MCU is in its low power state. | |
* | |
*/ | |
/* ASF includes. */ | |
#include <asf.h> | |
/* Kernel includes. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
#include "queue.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 rate at which the Tx task sends to the queue. */ | |
#define mainTX_DELAY ( 500UL / portTICK_PERIOD_MS ) | |
/* 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 length of time the LED will remain on for. It is on just long enough | |
to be able to see with the human eye so as not to distort the power readings too | |
much. */ | |
#define mainLED_TOGGLE_DELAY ( 20 / portTICK_PERIOD_MS ) | |
/*-----------------------------------------------------------*/ | |
/* | |
* The Rx and Tx tasks as described at the top of this file. | |
*/ | |
static void prvQueueReceiveTask( void *pvParameters ); | |
static void prvQueueSendTask( void *pvParameters ); | |
/*-----------------------------------------------------------*/ | |
/* The queue to pass data from the Tx task to the Rx task. */ | |
static QueueHandle_t xQueue = NULL; | |
/*-----------------------------------------------------------*/ | |
void main_low_power( void ) | |
{ | |
/* Create the queue. */ | |
xQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( unsigned long ) ); | |
configASSERT( xQueue ); | |
/* 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 ); | |
/* 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 ) | |
{ | |
const unsigned long ulValueToSend = mainQUEUED_VALUE; | |
/* Remove compiler warning about unused parameter. */ | |
( void ) pvParameters; | |
for( ;; ) | |
{ | |
/* Place this task into the blocked state until it is time to run again. | |
The kernel will place the MCU into the Retention low power sleep state | |
when the idle task next runs. */ | |
vTaskDelay( mainTX_DELAY ); | |
/* 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 already 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. */ | |
xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY ); | |
/* To get here something must have arrived, but is it the expected | |
value? If it is, turn the LED on for a short while. */ | |
if( ulReceivedValue == mainQUEUED_VALUE ) | |
{ | |
vParTestSetLED( mainQUEUE_LED, pdTRUE ); | |
vTaskDelay( mainLED_TOGGLE_DELAY ); | |
vParTestSetLED( mainQUEUE_LED, pdFALSE ); | |
} | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
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, peripherals can 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; | |
} | |
/*-----------------------------------------------------------*/ | |
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; | |
} | |
/*-----------------------------------------------------------*/ | |