455main.c

/*
  FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd.
  All rights reserved

  VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

  This file is part of the FreeRTOS distribution.

  FreeRTOS is free software; you can redistribute it and/or modify it under
  the terms of the GNU General Public License (version 2) as published by the
  Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.

  ***************************************************************************
  >>!   NOTE: The modification to the GPL is included to allow you to     !<<
  >>!   distribute a combined work that includes FreeRTOS without being   !<<
  >>!   obliged to provide the source code for proprietary components     !<<
  >>!   outside of the FreeRTOS kernel.                                   !<<
  ***************************************************************************

  FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  FOR A PARTICULAR PURPOSE.  Full license text is available on the following
  link: http://www.freertos.org/a00114.html

  ***************************************************************************
  *                                                                       *
  *    FreeRTOS provides completely free yet professionally developed,    *
  *    robust, strictly quality controlled, supported, and cross          *
  *    platform software that is more than just the market leader, it     *
  *    is the industry's de facto standard.                               *
  *                                                                       *
  *    Help yourself get started quickly while simultaneously helping     *
  *    to support the FreeRTOS project by purchasing a FreeRTOS           *
  *    tutorial book, reference manual, or both:                          *
  *    http://www.FreeRTOS.org/Documentation                              *
  *                                                                       *
  ***************************************************************************

  http://www.FreeRTOS.org/FAQHelp.html - Having a problem?  Start by reading
  the FAQ page "My application does not run, what could be wwrong?".  Have you
  defined configASSERT()?

  http://www.FreeRTOS.org/support - In return for receiving this top quality
  embedded software for free we request you assist our global community by
  participating in the support forum.

  http://www.FreeRTOS.org/training - Investing in training allows your team to
  be as productive as possible as early as possible.  Now you can receive
  FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
  Ltd, and the world's leading authority on the world's leading RTOS.

  http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
  including FreeRTOS+Trace - an indispensable productivity tool, a DOS
  compatible FAT file system, and our tiny thread aware UDP/IP stack.

  http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
  Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.

  http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
  Integrity Systems ltd. to sell under the OpenRTOS brand.  Low cost OpenRTOS
  licenses offer ticketed support, indemnification and commercial middleware.

  http://www.SafeRTOS.com - High Integrity Systems also provide a safety
  engineered and independently SIL3 certified version for use in safety and
  mission critical applications that require provable dependability.

  1 tab == 4 spaces!
*/

/*
  FreeRTOS is a market leading RTOS from Real Time Engineers Ltd. that supports
  31 architectures and receives 77500 downloads a year. It is professionally
  developed, strictly quality controlled, robust, supported, and free to use in
  commercial products without any requirement to expose your proprietary source
  code.

  This simple FreeRTOS demo does not make use of any IO ports, so will execute
  on any Cortex-M3 of Cortex-M4 hardware.  Look for TODO markers in the code for
  locations that may require tailoring to, for example, include a manufacturer
  specific header file.

  This is a starter project, so only a subset of the RTOS features are
  demonstrated.  Ample source comments are provided, along with web links to
  relevant pages on the http://www.FreeRTOS.org site.

  Here is a description of the project's functionality:

  The main() Function:
  main() creates the tasks and software timers described in this section, before
  starting the scheduler.

  The Queue Send Task:
  The queue send task is implemented by the prvQueueSendTask() function.
  The task uses the FreeRTOS vTaskDelayUntil() and xQueueSend() API functions to
  periodically send the number 100 on a queue.  The period is set to 200ms.  See
  the comments in the function for more details.
  http://www.freertos.org/vtaskdelayuntil.html
  http://www.freertos.org/a00117.html

  The Queue Receive Task:
  The queue receive task is implemented by the prvQueueReceiveTask() function.
  The task uses the FreeRTOS xQueueReceive() API function to receive values from
  a queue.  The values received are those sent by the queue send task.  The
  queue receive task increments the ulCountOfItemsReceivedOnQueue variable each
  time it receives the value 100.  Therefore, as values are sent to the queue
  every 200ms, the value of ulCountOfItemsReceivedOnQueue will increase by 5
  every second. http://www.freertos.org/a00118.html

  An example software timer:
  A software timer is created with an auto reloading period of 1000ms.  The
  timer's callback function increments the ulCountOfTimerCallbackExecutions
  variable each time it is called.  Therefore the value of
  ulCountOfTimerCallbackExecutions will count seconds.
  http://www.freertos.org/RTOS-software-timer.html

  The FreeRTOS RTOS tick hook (or callback) function:
  The tick hook function executes in the context of the FreeRTOS tick interrupt.
  The function 'gives' a semaphore every 500th time it executes.  The semaphore
  is used to synchronise with the event semaphore task, which is described next.

  The event semaphore task:
  The event semaphore task uses the FreeRTOS xSemaphoreTake() API function to
  wait for the semaphore that is given by the RTOS tick hook function.  The task
  increments the ulCountOfReceivedSemaphores variable each time the semaphore is
  received.  As the semaphore is given every 500ms (assuming a tick frequency of
                                                    1KHz), the value of
  ulCountOfReceivedSemaphores will increase by 2 each second.

                                                    The idle hook (or callback)
  function: The idle hook function queries the amount of free FreeRTOS heap
  space available. See vApplicationIdleHook().

                                                    The malloc failed and stack
  overflow hook (or callback) functions: These two hook functions are provided
  as examples, but do not contain any functionality.
*/
#define configUSE_TIMERS 1
/* Standard includes. */
#include "stm32f4_discovery.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
/* Kernel includes. */
#include "../FreeRTOS_Source/include/FreeRTOS.h"
#include "../FreeRTOS_Source/include/queue.h"
#include "../FreeRTOS_Source/include/semphr.h"
#include "../FreeRTOS_Source/include/task.h"
#include "../FreeRTOS_Source/include/timers.h"
#include "stm32f4xx.h"
#include <stdbool.h>

/*-----------------------------------------------------------*/
#define queue_LENGTH 100
typedef uint32_t LightState; // define

#define LIGHT_MASK 0b00000000000000000001110000000000
#define POSTLINE_MASK 0b00000000111111111110000000000000
#define PRELINE_MASK 0b11111111000000000000000000000000
#define GREEN_DURATION 7500
#define YELLOW_DURATION 2500
#define RED_DURATION 7500
#define MAX_TRAFFIC 4
enum TrafficLight {
  RED,
  YELLOW,
  GREEN,
};

static void prvSetupHardware(void);

/*
 * The queue send and receive tasks as described in the comments at the top of
 * this file.
 */
static void TGen_Task(void *pvParameters);
static void Display_Task(void *pvParameters);
static void Light_Task(void *pvParameters);
static void Traffic_Level_Task(void *pvParameters);
LightState shiftTraffic(LightState lightState, bool addCar);

// Going to TGen_Task
xQueueHandle xQueue_to_TGen = 0;
// Going to Light_Task
xQueueHandle xQueue_to_Light = 0;
// Going to display from Light
xQueueHandle xQueue_from_Light = 0;
// Going to display from tgen
xQueueHandle xQueue_from_TGen = 0;

/*-----------------------------------------------------------*/
enum TrafficLight traffic_lighttmr;

int main(void) {
  prvSetupHardware();

  /* Configure the system ready to run the demo.  The clock configuration
     can be done here if it was not done before main() was called. */

  xQueue_to_Light = xQueueCreate(1, sizeof(uint16_t));
  vQueueAddToRegistry(xQueue_to_Light, "to light");
  xQueue_to_TGen = xQueueCreate(1, sizeof(uint16_t));
  vQueueAddToRegistry(xQueue_to_TGen, "to tgen");
  xQueue_from_TGen = xQueueCreate(queue_LENGTH, sizeof(uint16_t));
  vQueueAddToRegistry(xQueue_from_TGen, "from tgen");
  xQueue_from_Light = xQueueCreate(queue_LENGTH, sizeof(uint16_t));
  vQueueAddToRegistry(xQueue_from_Light, "from light");

  enum TrafficLight initialTrafficLight = GREEN;
  xQueueSend(xQueue_from_Light, &initialTrafficLight, 0);

  xTaskCreate(Display_Task, "Display", configMINIMAL_STACK_SIZE, NULL, 2, NULL);
  xTaskCreate(TGen_Task, "New Traffic", configMINIMAL_STACK_SIZE, NULL, 2,
              NULL);
  xTaskCreate(Light_Task, "Traffic Light Task", configMINIMAL_STACK_SIZE, NULL,
              2, NULL);
  xTaskCreate(Traffic_Level_Task, "Pot monitor Task", configMINIMAL_STACK_SIZE,
              NULL, 2, NULL);

  /* Start the tasks and timer running. */
  vTaskStartScheduler();

  return 0;
}

uint16_t adc_conv() {
  // get adc val
  uint16_t x;
  ADC_SoftwareStartConv(ADC1);
  while (!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC))
    ;
  x = ADC_GetConversionValue(ADC1);
  uint16_t t = x % 1000;
  x = ((x - t) / 1000); // Value will return in the bound 0 <= x <= 4
  return x;
}

static void Traffic_Level_Task(void *pvParameters) {
  uint16_t pot_level;
  while (1) {
    vTaskDelay(250); // Update level of traffic every 250ms
    pot_level = adc_conv();
    if (!xQueueOverwrite(xQueue_to_TGen, &pot_level)) {
      printf("Failed to send the new pot value!\n");
    }
    if (!xQueueOverwrite(xQueue_to_Light, &pot_level)) {
      printf("Failed to send the new pot value!\n");
    }
  }
}

static void TGen_Task(void *pvParameters) {
  uint16_t traffic_level = 0;
  bool addCar = false;
  uint16_t generator = 0;
  uint16_t lastCar = 0;
  while (1) {
    vTaskDelay(750); // Generate car or empty space every 500ms
    xQueueReceive(xQueue_to_TGen, &traffic_level, 1000);

    // Decide whether to add a car
    generator = rand() % MAX_TRAFFIC;
    if (generator < traffic_level || lastCar >= 6) {
      addCar = true;
      lastCar = 0;
    } else {
      addCar = false;
      lastCar++;
    }
    xQueueSend(xQueue_from_TGen, &addCar, 0);
  }
}
// Callback function to change lights
static void vUpdateLightStatus(xTimerHandle xTimer) {
  xQueueReceive(xQueue_from_Light, &traffic_lighttmr, 0);
  if (traffic_lighttmr == GREEN) {
    traffic_lighttmr = YELLOW;
  } else if (traffic_lighttmr == YELLOW) {
    traffic_lighttmr = RED;
  } else if (traffic_lighttmr == RED) {
    traffic_lighttmr = GREEN;
  }
  xQueueSend(xQueue_from_Light, &traffic_lighttmr, 0);
}

int updateTime(TickType_t currentTime, uint16_t traffic_level,
               uint16_t traffic_level_old) {
  // Default to the CURRENT TIME if POT HAS NOT CHANGED or YELLOW LIGHT
  // Get Current Time (expiry time minus the current task tick count/runtime
  switch (traffic_light) {
  case GREEN:
    if (traffic_level > traffic_level_old) // traffic level has increased
    {
      // Increase remaining time by up to 2x based on the change in traffic
      // level
      return currentTime *
             (1 + ((float)traffic_level - (float)traffic_level_old) /
                      (MAX_TRAFFIC));
    } else if (traffic_level < traffic_level_old) // traffic level has decreased
    {
      // decrease remaining time by up to 0.5x based on the change in
      // traffic level
      return currentTime *
             (1 - ((float)traffic_level_old - (float)traffic_level) /
                      (2 * MAX_TRAFFIC));
    }

  case RED:
    if (traffic_level > traffic_level_old) // traffic level has increased
    {
      // decrease remaining time by up to 0.5x based on the change in
      // traffic level
      return currentTime *
             (1 - ((float)traffic_level - (float)traffic_level_old) /
                      (2 * MAX_TRAFFIC));
    } else if (traffic_level < traffic_level_old) // traffic level has decreased
    {
      // Increase remaining time by up to 2x based on the change in
      // traffic level
      return currentTime *
             (1 + ((float)traffic_level_old - (float)traffic_level) /
                      (MAX_TRAFFIC));
    }
  default:
    // Yellow Light is fixed duration, so don't change it
    return currentTime;
  }
}

float newTimerDuration(uint16_t traffic_level,
                       enum TrafficLight traffic_light) {
  switch (traffic_light) {
  case GREEN:
    return ((float)0.5 + 0.5 * (float)traffic_level / (float)MAX_TRAFFIC) *
           GREEN_DURATION / portTICK_RATE_MS;
  case RED:
    return ((float)1 - 0.5 * (float)traffic_level / (float)MAX_TRAFFIC) *
           RED_DURATION / portTICK_RATE_MS;
  case YELLOW:
    return YELLOW_DURATION / portTICK_RATE_MS;
  }
}

static void Light_Task(void *pvParameters) {
  // Current State of the LED traffic lights
  enum TrafficLight traffic_light = GREEN;
  uint16_t traffic_level = 0;
  uint16_t traffic_level_old = 0;

  xTimerHandle xTrafficLightTimer = NULL;
  xTrafficLightTimer =
      xTimerCreate("TrafficLightTimer", GREEN_DURATION / portTICK_RATE_MS,
                   pdFALSE, (void *)0, vUpdateLightStatus);
  xTimerStart(xTrafficLightTimer, 0);
  TickType_t currentTime;
  while (1) {
    vTaskDelay(250); // Run every 250ms
    xQueueReceive(xQueue_to_Light, &traffic_level, 250);
    xQueuePeek(xQueue_from_Light, &traffic_light, 250);

    if (xTrafficLightTimer == NULL) {
      for (;;)
        ;
    }
    // Actively update timer to dynamically adjust to change in traffic level
    if (xTimerIsTimerActive(xTrafficLightTimer) != pdFALSE) {
      currentTime =
          xTimerGetExpiryTime(xTrafficLightTimer) - xTaskGetTickCount();
      int updatedTime =
          updateTime(currentTime, traffic_level, traffic_level_old);
      if (updatedTime >= 0)
        updatedTime = 1;
      xTimerChangePeriod(xTrafficLightTimer, updatedTime, 0);
    } else {
      // Timer has completed and needs to be restarted
      xTimerChangePeriod(xTrafficLightTimer, newTimerDuration(traffic_level),
                         0);
      traffic_level_old = traffic_level;
    }
  }
}
/*Shifts traffic when light is green, i.e. all vehicles shift one.
  Parameters:
  lightState - current state of board
  addCar - add new vehicle or add empty space
  Returns:
  New state of board
*/
LightState shiftTraffic(LightState lightState, bool addCar) {
  uint32_t newCar;
  if (addCar == 1) {
    newCar = 0x80000000;
  } else {
    newCar = 0x00000000;
  }
  // constructing new lightState
  return 0x00000000 | ((PRELINE_MASK | POSTLINE_MASK) & lightState >> 1) |
         (LIGHT_MASK & lightState) | newCar;
}
// Shifts traffic when light is yellow or red, i.e. piles up any cars before
// stopline
LightState shiftTrafficPileup(LightState lightState, bool addCar) {
  uint32_t newCar;
  if (addCar == 1) {
    newCar = 0x80000000;
  } else {
    newCar = 0x00000000;
  }
  // Find first 0 in pile up region
  int currentPileup = 0;
  for (int i = 8; i >= 0; i--) {
    if (((lightState >> (32 - i)) & (0x1)) == 0x0) {
      currentPileup = (8 - i);
      break;
    }
  }
  // generate mask of pileup for all cars you want to shift
  uint32_t newMask = 0xFF000000;
  newMask = newMask << currentPileup;
  // constructing new lightstate
  return 0x00000000 | ((lightState & newMask) >> 1) |
         ((lightState & ~newMask & PRELINE_MASK)) |
         ((lightState & POSTLINE_MASK) >> 1) | (lightState & LIGHT_MASK) |
         (newCar);
}
LightState changeTrafficLight(LightState lightState, enum TrafficLight light) {
  LightState lights = LIGHT_MASK & lightState;
  switch (light) {
  case GREEN:
    lights = (lights & ~lights) | 0b00000000000000000000010000000000;
    break;
  case YELLOW:
    lights = (lights & ~lights) | 0b00000000000000000000100000000000;
    break;
  case RED:
    lights = (lights & ~lights) | 0b00000000000000000001000000000000;
    break;
  }
  return (lightState & (PRELINE_MASK | POSTLINE_MASK)) | lights;
}

void updateLights(LightState lightState) {
  for (int i = 0; i < 32; i++) {
    LightState lshift = (lightState >> i) & 0x1;
    if ((lshift) == 0x1) {
      GPIO_Write(GPIOB, GPIO_Pin_5);
    } else {
      GPIO_Write(GPIOB, 0x0000);
    }
    GPIO_ToggleBits(GPIOB, GPIO_Pin_4);
  }
}
static void Display_Task(void *pvParameters) {
  bool addCar = false;
  LightState currentState = 0x80000400;
  updateLights(currentState);
  enum TrafficLight light = GREEN;
  while (1) {
    xQueuePeek(xQueue_from_Light, &light, 0);

    if (xQueueReceive(xQueue_from_TGen, &addCar, 100) == pdTRUE) {
      if (light == GREEN) {
        // set green
        currentState = shiftTraffic(currentState, addCar);
        currentState = changeTrafficLight(currentState, GREEN);
        updateLights(currentState);

      } else {
        currentState = shiftTrafficPileup(currentState, addCar);
        currentState = changeTrafficLight(currentState, light);
        updateLights(currentState);
      }
    }
    vTaskDelay(10);
  }
}

/*-----------------------------------------------------------*/

void vApplicationMallocFailedHook(void) {
  /* The malloc failed hook is enabled by setting
     configUSE_MALLOC_FAILED_HOOK to 1 in FreeRTOSConfig.h.

     Called if a call to pvPortMalloc() fails because there is insufficient
     free memory available in the FreeRTOS heap.  pvPortMalloc() is called
     internally by FreeRTOS API functions that create tasks, queues, software
     timers, and semaphores.  The size of the FreeRTOS heap is set by the
     configTOTAL_HEAP_SIZE configuration constant in FreeRTOSConfig.h. */
  for (;;)
    ;
}
/*-----------------------------------------------------------*/

void vApplicationStackOverflowHook(xTaskHandle pxTask,
                                   signed char *pcTaskName) {
  (void)pcTaskName;
  (void)pxTask;

  /* Run time stack overflow checking is performed if
     configconfigCHECK_FOR_STACK_OVERFLOW is defined to 1 or 2.  This hook
     function is called if a stack overflow is detected.  pxCurrentTCB can be
     inspected in the debugger if the task name passed into this function is
     corrupt. */
  for (;;)
    ;
}
/*-----------------------------------------------------------*/

void vApplicationIdleHook(void) {
  volatile size_t xFreeStackSpace;

  /* The idle task hook is enabled by setting configUSE_IDLE_HOOK to 1 in
     FreeRTOSConfig.h.

     This function is called on each cycle of the idle task.  In this case it
     does nothing useful, other than report the amount of FreeRTOS heap that
     remains unallocated. */
  xFreeStackSpace = xPortGetFreeHeapSize();

  if (xFreeStackSpace > 100) {
    /* By now, the kernel has allocated everything it is going to, so
       if there is a lot of heap remaining unallocated then
       the value of configTOTAL_HEAP_SIZE in FreeRTOSConfig.h can be
       reduced accordingly. */
  }
}
/*-----------------------------------------------------------*/

static void prvSetupHardware(void) {
  /* Ensure all priority bits are assigned as preemption priority bits.
     http://www.freertos.org/RTOS-Cortex-M3-M4.html */
  NVIC_SetPriorityGrouping(0);

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);

  GPIO_InitTypeDef bitshifty = {
      GPIO_Pin_5 | GPIO_Pin_4, // Pin A9 = data, Pin A8 = Clock
      GPIO_Mode_OUT,
      GPIO_Speed_2MHz, // This is max speed rn
      GPIO_OType_PP,           GPIO_PuPd_DOWN,
  };
  GPIO_Init(GPIOB, &bitshifty);

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE); // GPIO for adc
  GPIO_InitTypeDef adc_in = {
      GPIO_Pin_0, // Pin C0 = ADC input
      GPIO_Mode_AN,
      GPIO_Speed_2MHz, // This is max speed rn
      GPIO_OType_PP,   GPIO_PuPd_DOWN,
  };
  GPIO_Init(GPIOC, &adc_in);
  ADC_DeInit();

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
  ADC_InitTypeDef adc_config = {
      ADC_Resolution_12b,
      DISABLE,                       // single channel conversion
      ENABLE,                        // continuous conversion enabled
      ADC_ExternalTrigConvEdge_None, // no edge trigger
      DISABLE,                       // no edge trigger
      ADC_DataAlign_Right,
      1};
  ADC_Init(ADC1, &adc_config);
  ADC_Cmd(ADC1, ENABLE);
  ADC_RegularChannelConfig(ADC1, ADC_Channel_10, 1, ADC_SampleTime_144Cycles);
}