如何使用timer的OSTmrCreate來實現MicroC / OS II的任務調度？
[英]How to use timer's OSTmrCreate to implement task scheduling with MicroC/OS II?
問題描述
我在MicroC中有2個任務來模擬移動的車輛：ControlTask和VehicleTask。 現在我的項目應該用定時器替換上下文切換以獲得更合適的時序，但我似乎無法完成它。 程序現在使用語句OSTimeDlyHMSM來實現句點，但軟計時器應該與信號量一起使用。 OSTmrCreate in C / OS-II ReferenceManual（第16章）。 我可以啟動一個計時器，然后我可以將它放在啟動代碼中但是我沒有調用計時器並在兩個任務之間正確同步，用計時器替換OSTimeDlyHMSM 。 我認為我的解決方案變得越來越復雜，因為我可能不了解所有細節，例如為什么我需要信號量以及為什么使用計時器比內置的OSTimeDlyHMSM更精確。 我到目前為止完成的工作如下：
#include <stdio.h>
#include "system.h"
#include "includes.h"
#include "altera_avalon_pio_regs.h"
#include "sys/alt_irq.h"
#include "sys/alt_alarm.h"
#define DEBUG 1
#define HW_TIMER_PERIOD 100 /* 100ms */
/* Button Patterns */
#define GAS_PEDAL_FLAG 0x08
#define BRAKE_PEDAL_FLAG 0x04
#define CRUISE_CONTROL_FLAG 0x02
/* Switch Patterns */
#define TOP_GEAR_FLAG 0x00000002
#define ENGINE_FLAG 0x00000001
/* LED Patterns */
#define LED_RED_0 0x00000001 // Engine
#define LED_RED_1 0x00000002 // Top Gear
#define LED_GREEN_0 0x0001 // Cruise Control activated
#define LED_GREEN_2 0x0002 // Cruise Control Button
#define LED_GREEN_4 0x0010 // Brake Pedal
#define LED_GREEN_6 0x0040 // Gas Pedal
/*
* Definition of Tasks
*/
#define TASK_STACKSIZE 2048
OS_STK StartTask_Stack[TASK_STACKSIZE];
OS_STK ControlTask_Stack[TASK_STACKSIZE];
OS_STK VehicleTask_Stack[TASK_STACKSIZE];
// Task Priorities
#define STARTTASK_PRIO 5
#define VEHICLETASK_PRIO 10
#define CONTROLTASK_PRIO 12
// Task Periods
#define CONTROL_PERIOD 300
#define VEHICLE_PERIOD 300
/*
* Definition of Kernel Objects
*/
// Mailboxes
OS_EVENT *Mbox_Throttle;
OS_EVENT *Mbox_Velocity;
// Semaphores
OS_EVENT *aSemaphore;
// SW-Timer
OS_TMR *SWTimer;
OS_TMR *SWTimer1;
BOOLEAN status;
/*
* Types
*/
enum active {on, off};
enum active gas_pedal = off;
enum active brake_pedal = off;
enum active top_gear = off;
enum active engine = off;
enum active cruise_control = off;
/*
* Global variables
*/
int delay; // Delay of HW-timer
INT16U led_green = 0; // Green LEDs
INT32U led_red = 0; // Red LEDs
int sharedMemory=1;
void ContextSwitch()
{
printf("ContextSwitch!\n");
sharedMemory=sharedMemory*-1;
}
int buttons_pressed(void)
{
return ~IORD_ALTERA_AVALON_PIO_DATA(DE2_PIO_KEYS4_BASE);
}
int switches_pressed(void)
{
return IORD_ALTERA_AVALON_PIO_DATA(DE2_PIO_TOGGLES18_BASE);
}
/*
* ISR for HW Timer
*/
alt_u32 alarm_handler(void* context)
{
OSTmrSignal(); /* Signals a 'tick' to the SW timers */
return delay;
}
static int b2sLUT[] = {0x40, //0
0x79, //1
0x24, //2
0x30, //3
0x19, //4
0x12, //5
0x02, //6
0x78, //7
0x00, //8
0x18, //9
0x3F, //-
};
/*
* convert int to seven segment display format
*/
int int2seven(int inval){
return b2sLUT[inval];
}
/*
* output current velocity on the seven segement display
*/
void show_velocity_on_sevenseg(INT8S velocity){
int tmp = velocity;
int out;
INT8U out_high = 0;
INT8U out_low = 0;
INT8U out_sign = 0;
if(velocity < 0){
out_sign = int2seven(10);
tmp *= -1;
}else{
out_sign = int2seven(0);
}
out_high = int2seven(tmp / 10);
out_low = int2seven(tmp - (tmp/10) * 10);
out = int2seven(0) << 21 |
out_sign << 14 |
out_high << 7 |
out_low;
IOWR_ALTERA_AVALON_PIO_DATA(DE2_PIO_HEX_LOW28_BASE,out);
}
/*
* shows the target velocity on the seven segment display (HEX5, HEX4)
* when the cruise control is activated (0 otherwise)
*/
void show_target_velocity(INT8U target_vel)
{
}
/*
* indicates the position of the vehicle on the track with the four leftmost red LEDs
* LEDR17: [0m, 400m)
* LEDR16: [400m, 800m)
* LEDR15: [800m, 1200m)
* LEDR14: [1200m, 1600m)
* LEDR13: [1600m, 2000m)
* LEDR12: [2000m, 2400m]
*/
void show_position(INT16U position)
{
}
/*
* The function 'adjust_position()' adjusts the position depending on the
* acceleration and velocity.
*/
INT16U adjust_position(INT16U position, INT16S velocity,
INT8S acceleration, INT16U time_interval)
{
INT16S new_position = position + velocity * time_interval / 1000
+ acceleration / 2 * (time_interval / 1000) * (time_interval / 1000);
if (new_position > 24000) {
new_position -= 24000;
} else if (new_position < 0){
new_position += 24000;
}
show_position(new_position);
return new_position;
}
/*
* The function 'adjust_velocity()' adjusts the velocity depending on the
* acceleration.
*/
INT16S adjust_velocity(INT16S velocity, INT8S acceleration,
enum active brake_pedal, INT16U time_interval)
{
INT16S new_velocity;
INT8U brake_retardation = 200;
if (brake_pedal == off)
new_velocity = velocity + (float) (acceleration * time_interval) / 1000.0;
else {
if (brake_retardation * time_interval / 1000 > velocity)
new_velocity = 0;
else
new_velocity = velocity - brake_retardation * time_interval / 1000;
}
return new_velocity;
}
/*
* The task 'VehicleTask' updates the current velocity of the vehicle
*/
void VehicleTask(void* pdata)
{
INT8U err;
void* msg;
INT8U* throttle;
INT8S acceleration; /* Value between 40 and -20 (4.0 m/s^2 and -2.0 m/s^2) */
INT8S retardation; /* Value between 20 and -10 (2.0 m/s^2 and -1.0 m/s^2) */
INT16U position = 0; /* Value between 0 and 20000 (0.0 m and 2000.0 m) */
INT16S velocity = 0; /* Value between -200 and 700 (-20.0 m/s amd 70.0 m/s) */
INT16S wind_factor; /* Value between -10 and 20 (2.0 m/s^2 and -1.0 m/s^2) */
printf("Vehicle task created!\n");
while(1)
{
err = OSMboxPost(Mbox_Velocity, (void *) &velocity);
OSTimeDlyHMSM(0,0,0,VEHICLE_PERIOD);
/* Non-blocking read of mailbox:
- message in mailbox: update throttle
- no message: use old throttle
*/
msg = OSMboxPend(Mbox_Throttle, 1, &err);
if (err == OS_NO_ERR)
throttle = (INT8U*) msg;
/* Retardation : Factor of Terrain and Wind Resistance */
if (velocity > 0)
wind_factor = velocity * velocity / 10000 + 1;
else
wind_factor = (-1) * velocity * velocity / 10000 + 1;
if (position < 4000)
retardation = wind_factor; // even ground
else if (position < 8000)
retardation = wind_factor + 15; // traveling uphill
else if (position < 12000)
retardation = wind_factor + 25; // traveling steep uphill
else if (position < 16000)
retardation = wind_factor; // even ground
else if (position < 20000)
retardation = wind_factor - 10; //traveling downhill
else
retardation = wind_factor - 5 ; // traveling steep downhill
acceleration = *throttle / 2 - retardation;
position = adjust_position(position, velocity, acceleration, 300);
velocity = adjust_velocity(velocity, acceleration, brake_pedal, 300);
printf("Position: %dm\n", position / 10);
printf("Velocity: %4.1fm/s\n", velocity /10.0);
printf("Throttle: %dV\n", *throttle / 10);
show_velocity_on_sevenseg((INT8S) (velocity / 10));
}
}
/*
* The task 'ControlTask' is the main task of the application. It reacts
* on sensors and generates responses.
*/
void ControlTask(void* pdata)
{
INT8U err;
INT8U throttle = 40; /* Value between 0 and 80, which is interpreted as between 0.0V and 8.0V */
void* msg;
INT16S* current_velocity;
printf("Control Task created!\n");
while(1)
{
msg = OSMboxPend(Mbox_Velocity, 0, &err);
current_velocity = (INT16S*) msg;
err = OSMboxPost(Mbox_Throttle, (void *) &throttle);
OSTimeDlyHMSM(0,0,0, CONTROL_PERIOD);
}
}
/*
* The task 'StartTask' creates all other tasks kernel objects and
* deletes itself afterwards.
*/
void StartTask(void* pdata)
{
INT8U err;
void* context;
static alt_alarm alarm; /* Is needed for timer ISR function */
/* Base resolution for SW timer : HW_TIMER_PERIOD ms */
delay = alt_ticks_per_second() * HW_TIMER_PERIOD / 1000;
printf("delay in ticks %d\n", delay);
/*
* Create Hardware Timer with a period of 'delay'
*/
if (alt_alarm_start (&alarm,
delay,
alarm_handler,
context) < 0)
{
printf("No system clock available!n");
}
/*
* Create and start Software Timer
*/
SWTimer = OSTmrCreate(0,
CONTROL_PERIOD/(4*OS_TMR_CFG_TICKS_PER_SEC),
OS_TMR_OPT_PERIODIC,
ContextSwitch,
NULL,
NULL,
&err);
if (err == OS_ERR_NONE) {
/* Timer was created but NOT started */
printf("SWTimer was created but NOT started \n");
}
status = OSTmrStart(SWTimer,
&err);
if (err == OS_ERR_NONE) {
/* Timer was started */
printf("SWTimer was started!\n");
}
/*
* Creation of Kernel Objects
*/
// Mailboxes
Mbox_Throttle = OSMboxCreate((void*) 0); /* Empty Mailbox - Throttle */
Mbox_Velocity = OSMboxCreate((void*) 0); /* Empty Mailbox - Velocity */
/*
* Create statistics task
*/
OSStatInit();
/*
* Creating Tasks in the system
*/
err = OSTaskCreateExt(
ControlTask, // Pointer to task code
NULL, // Pointer to argument that is
// passed to task
&ControlTask_Stack[TASK_STACKSIZE-1], // Pointer to top
// of task stack
CONTROLTASK_PRIO,
CONTROLTASK_PRIO,
(void *)&ControlTask_Stack[0],
TASK_STACKSIZE,
(void *) 0,
OS_TASK_OPT_STK_CHK);
err = OSTaskCreateExt(
VehicleTask, // Pointer to task code
NULL, // Pointer to argument that is
// passed to task
&VehicleTask_Stack[TASK_STACKSIZE-1], // Pointer to top
// of task stack
VEHICLETASK_PRIO,
VEHICLETASK_PRIO,
(void *)&VehicleTask_Stack[0],
TASK_STACKSIZE,
(void *) 0,
OS_TASK_OPT_STK_CHK);
printf("All Tasks and Kernel Objects generated!\n");
/* Task deletes itself */
OSTaskDel(OS_PRIO_SELF);
}
/*
*
* The function 'main' creates only a single task 'StartTask' and starts
* the OS. All other tasks are started from the task 'StartTask'.
*
*/
int main(void) {
printf("Cruise Control\n");
aSemaphore = OSSemCreate(1); // binary semaphore (1 key)
OSTaskCreateExt(
StartTask, // Pointer to task code
NULL, // Pointer to argument that is
// passed to task
(void *)&StartTask_Stack[TASK_STACKSIZE-1], // Pointer to top
// of task stack
STARTTASK_PRIO,
STARTTASK_PRIO,
(void *)&StartTask_Stack[0],
TASK_STACKSIZE,
(void *) 0,
OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR);
OSStart();
return 0;
}
運行上面的程序回調contextswitch被執行但它還沒有解決使用定時器而不是內置yield的問題以及如何將它應用於信號量。
Cruise Control
delay in ticks 100
SWTimer was created but NOT started
SWTimer was started!
All Tasks and Kernel Objects generated!
Vehicle task created!
Control Task created!
ContextSwitch!
Position: 0m
Velocity: 0.5m/s
Throttle: 4V
ContextSwitch!
Position: 0m
Velocity: 1.0m/s
Throttle: 4V
Position: 0m
Velocity: 1.5m/s
Throttle: 4V
ContextSwitch!
Position: 0m
Velocity: 2.0m/s
Throttle: 4V
ContextSwitch!
Position: 1m
Velocity: 2.5m/s
Throttle: 4V
ContextSwitch!
Position: 2m
Velocity: 3.0m/s
Throttle: 4V
ContextSwitch!
更新141001 15:57 CET
2個信號量+ 2個定時器似乎是一個很好的改進。 我希望它可以檢查或測試......
#include <stdio.h>
#include "system.h"
#include "includes.h"
#include "altera_avalon_pio_regs.h"
#include "sys/alt_irq.h"
#include "sys/alt_alarm.h"
#define DEBUG 1
#define HW_TIMER_PERIOD 100 /* 100ms */
/* Button Patterns */
#define GAS_PEDAL_FLAG 0x08
#define BRAKE_PEDAL_FLAG 0x04
#define CRUISE_CONTROL_FLAG 0x02
/* Switch Patterns */
#define TOP_GEAR_FLAG 0x00000002
#define ENGINE_FLAG 0x00000001
/* LED Patterns */
#define LED_RED_0 0x00000001 // Engine
#define LED_RED_1 0x00000002 // Top Gear
#define LED_GREEN_0 0x0001 // Cruise Control activated
#define LED_GREEN_2 0x0002 // Cruise Control Button
#define LED_GREEN_4 0x0010 // Brake Pedal
#define LED_GREEN_6 0x0040 // Gas Pedal
/*
* Definition of Tasks
*/
#define TASK_STACKSIZE 2048
OS_STK StartTask_Stack[TASK_STACKSIZE];
OS_STK ControlTask_Stack[TASK_STACKSIZE];
OS_STK VehicleTask_Stack[TASK_STACKSIZE];
// Task Priorities
#define STARTTASK_PRIO 5
#define VEHICLETASK_PRIO 10
#define CONTROLTASK_PRIO 12
// Task Periods
#define CONTROL_PERIOD 300
#define VEHICLE_PERIOD 300
/*
* Definition of Kernel Objects
*/
// Mailboxes
OS_EVENT *Mbox_Throttle;
OS_EVENT *Mbox_Velocity;
// Semaphores
OS_EVENT *aSemaphore;
OS_EVENT *aSemaphore2;
// SW-Timer
OS_TMR *SWTimer;
OS_TMR *SWTimer1;
BOOLEAN status;
/*
* Types
*/
enum active {on, off};
enum active gas_pedal = off;
enum active brake_pedal = off;
enum active top_gear = off;
enum active engine = off;
enum active cruise_control = off;
/*
* Global variables
*/
int delay; // Delay of HW-timer
INT16U led_green = 0; // Green LEDs
INT32U led_red = 0; // Red LEDs
int sharedMemory=1;
void TimerCallback(params)
{
// Post to the semaphore to signal that it's time to run the task.
OSSemPost(aSemaphore); // Releasing the key
}
void ContextSwitch()
{
printf("ContextSwitch!\n");
sharedMemory=sharedMemory*-1;
}
int buttons_pressed(void)
{
return ~IORD_ALTERA_AVALON_PIO_DATA(DE2_PIO_KEYS4_BASE);
}
int switches_pressed(void)
{
return IORD_ALTERA_AVALON_PIO_DATA(DE2_PIO_TOGGLES18_BASE);
}
/*
* ISR for HW Timer
*/
alt_u32 alarm_handler(void* context)
{
OSTmrSignal(); /* Signals a 'tick' to the SW timers */
return delay;
}
void release()
{
printf("release key!\n");
//OSSemPost(aSemaphore); // Releasing the key
OSSemPost(aSemaphore2); // Releasing the key
printf("released key!\n");
}
void release2()
{
printf("release2!\n");
OSSemPost(aSemaphore2); // Releasing the key
printf("release2!\n");
}
static int b2sLUT[] = {0x40, //0
0x79, //1
0x24, //2
0x30, //3
0x19, //4
0x12, //5
0x02, //6
0x78, //7
0x00, //8
0x18, //9
0x3F, //-
};
/*
* convert int to seven segment display format
*/
int int2seven(int inval){
return b2sLUT[inval];
}
/*
* output current velocity on the seven segement display
*/
void show_velocity_on_sevenseg(INT8S velocity){
int tmp = velocity;
int out;
INT8U out_high = 0;
INT8U out_low = 0;
INT8U out_sign = 0;
if(velocity < 0){
out_sign = int2seven(10);
tmp *= -1;
}else{
out_sign = int2seven(0);
}
out_high = int2seven(tmp / 10);
out_low = int2seven(tmp - (tmp/10) * 10);
out = int2seven(0) << 21 |
out_sign << 14 |
out_high << 7 |
out_low;
IOWR_ALTERA_AVALON_PIO_DATA(DE2_PIO_HEX_LOW28_BASE,out);
}
/*
* shows the target velocity on the seven segment display (HEX5, HEX4)
* when the cruise control is activated (0 otherwise)
*/
void show_target_velocity(INT8U target_vel)
{
}
/*
* indicates the position of the vehicle on the track with the four leftmost red LEDs
* LEDR17: [0m, 400m)
* LEDR16: [400m, 800m)
* LEDR15: [800m, 1200m)
* LEDR14: [1200m, 1600m)
* LEDR13: [1600m, 2000m)
* LEDR12: [2000m, 2400m]
*/
void show_position(INT16U position)
{
}
/*
* The function 'adjust_position()' adjusts the position depending on the
* acceleration and velocity.
*/
INT16U adjust_position(INT16U position, INT16S velocity,
INT8S acceleration, INT16U time_interval)
{
INT16S new_position = position + velocity * time_interval / 1000
+ acceleration / 2 * (time_interval / 1000) * (time_interval / 1000);
if (new_position > 24000) {
new_position -= 24000;
} else if (new_position < 0){
new_position += 24000;
}
show_position(new_position);
return new_position;
}
/*
* The function 'adjust_velocity()' adjusts the velocity depending on the
* acceleration.
*/
INT16S adjust_velocity(INT16S velocity, INT8S acceleration,
enum active brake_pedal, INT16U time_interval)
{
INT16S new_velocity;
INT8U brake_retardation = 200;
if (brake_pedal == off)
new_velocity = velocity + (float) (acceleration * time_interval) / 1000.0;
else {
if (brake_retardation * time_interval / 1000 > velocity)
new_velocity = 0;
else
new_velocity = velocity - brake_retardation * time_interval / 1000;
}
return new_velocity;
}
/*
* The task 'VehicleTask' updates the current velocity of the vehicle
*/
void VehicleTask(void* pdata)
{
INT8U err;
void* msg;
INT8U* throttle;
INT8S acceleration; /* Value between 40 and -20 (4.0 m/s^2 and -2.0 m/s^2) */
INT8S retardation; /* Value between 20 and -10 (2.0 m/s^2 and -1.0 m/s^2) */
INT16U position = 0; /* Value between 0 and 20000 (0.0 m and 2000.0 m) */
INT16S velocity = 0; /* Value between -200 and 700 (-20.0 m/s amd 70.0 m/s) */
INT16S wind_factor; /* Value between -10 and 20 (2.0 m/s^2 and -1.0 m/s^2) */
printf("Vehicle task created!\n");
// Create a semaphore to represent the "it's time to run" event.
// Initialize the semaphore count to zero because it's not time
// to run yet.
// Create a periodic software timer which calls TimerCallback()
// when it expires.
/*
* Create and start Software Timer
*/
SWTimer1 = OSTmrCreate(0,
CONTROL_PERIOD/(4*OS_TMR_CFG_TICKS_PER_SEC),
OS_TMR_OPT_PERIODIC,
TimerCallback,
NULL,
NULL,
&err);
if (err == OS_ERR_NONE) {
/* Timer was created but NOT started */
printf("SWTimer1 was created but NOT started \n");
}
status = OSTmrStart(SWTimer1,
&err);
if (err == OS_ERR_NONE) {
/* Timer was started */
printf("SWTimer1 was started!\n");
}
while(1)
{
OSSemPend(aSemaphore, 0, &err); // Trying to access the key
err = OSMboxPost(Mbox_Velocity, (void *) &velocity);
//OSTimeDlyHMSM(0,0,0,VEHICLE_PERIOD);
/* Non-blocking read of mailbox:
- message in mailbox: update throttle
- no message: use old throttle
*/
msg = OSMboxPend(Mbox_Throttle, 1, &err);
if (err == OS_NO_ERR)
throttle = (INT8U*) msg;
/* Retardation : Factor of Terrain and Wind Resistance */
if (velocity > 0)
wind_factor = velocity * velocity / 10000 + 1;
else
wind_factor = (-1) * velocity * velocity / 10000 + 1;
if (position < 4000)
retardation = wind_factor; // even ground
else if (position < 8000)
retardation = wind_factor + 15; // traveling uphill
else if (position < 12000)
retardation = wind_factor + 25; // traveling steep uphill
else if (position < 16000)
retardation = wind_factor; // even ground
else if (position < 20000)
retardation = wind_factor - 10; //traveling downhill
else
retardation = wind_factor - 5 ; // traveling steep downhill
acceleration = *throttle / 2 - retardation;
position = adjust_position(position, velocity, acceleration, 300);
velocity = adjust_velocity(velocity, acceleration, brake_pedal, 300);
printf("Position: %dm\n", position / 10);
printf("Velocity: %4.1fm/s\n", velocity /10.0);
printf("Throttle: %dV\n", *throttle / 10);
show_velocity_on_sevenseg((INT8S) (velocity / 10));
//OSSemPost(aSemaphore); // Releasing the key
}
}
/*
* The task 'ControlTask' is the main task of the application. It reacts
* on sensors and generates responses.
*/
void ControlTask(void* pdata)
{
INT8U err;
INT8U throttle = 40; /* Value between 0 and 80, which is interpreted as between 0.0V and 8.0V */
void* msg;
INT16S* current_velocity;
printf("Control Task created!\n");
while(1)
{
OSSemPend(aSemaphore2, 0, &err); // Trying to access the key
msg = OSMboxPend(Mbox_Velocity, 0, &err);
current_velocity = (INT16S*) msg;
printf("Control Task!\n");
err = OSMboxPost(Mbox_Throttle, (void *) &throttle);
//OSSemPost(aSemaphore2); // Releasing the key
//OSTimeDlyHMSM(0,0,0, CONTROL_PERIOD);
}
}
/*
* The task 'StartTask' creates all other tasks kernel objects and
* deletes itself afterwards.
*/
void StartTask(void* pdata)
{
INT8U err;
void* context;
static alt_alarm alarm; /* Is needed for timer ISR function */
/* Base resolution for SW timer : HW_TIMER_PERIOD ms */
delay = alt_ticks_per_second() * HW_TIMER_PERIOD / 1000;
printf("delay in ticks %d\n", delay);
/*
* Create Hardware Timer with a period of 'delay'
*/
if (alt_alarm_start (&alarm,
delay,
alarm_handler,
context) < 0)
{
printf("No system clock available!n");
}
/*
* Create and start Software Timer
*/
SWTimer = OSTmrCreate(0,
CONTROL_PERIOD/(4*OS_TMR_CFG_TICKS_PER_SEC),
OS_TMR_OPT_PERIODIC,
release,
NULL,
NULL,
&err);
if (err == OS_ERR_NONE) {
/* Timer was created but NOT started */
printf("SWTimer was created but NOT started \n");
}
status = OSTmrStart(SWTimer,
&err);
if (err == OS_ERR_NONE) {
/* Timer was started */
printf("SWTimer was started!\n");
}
/*
* Creation of Kernel Objects
*/
// Mailboxes
Mbox_Throttle = OSMboxCreate((void*) 0); /* Empty Mailbox - Throttle */
Mbox_Velocity = OSMboxCreate((void*) 0); /* Empty Mailbox - Velocity */
/*
* Create statistics task
*/
OSStatInit();
/*
* Creating Tasks in the system
*/
err = OSTaskCreateExt(
ControlTask, // Pointer to task code
NULL, // Pointer to argument that is
// passed to task
&ControlTask_Stack[TASK_STACKSIZE-1], // Pointer to top
// of task stack
CONTROLTASK_PRIO,
CONTROLTASK_PRIO,
(void *)&ControlTask_Stack[0],
TASK_STACKSIZE,
(void *) 0,
OS_TASK_OPT_STK_CHK);
err = OSTaskCreateExt(
VehicleTask, // Pointer to task code
NULL, // Pointer to argument that is
// passed to task
&VehicleTask_Stack[TASK_STACKSIZE-1], // Pointer to top
// of task stack
VEHICLETASK_PRIO,
VEHICLETASK_PRIO,
(void *)&VehicleTask_Stack[0],
TASK_STACKSIZE,
(void *) 0,
OS_TASK_OPT_STK_CHK);
printf("All Tasks and Kernel Objects generated!\n");
/* Task deletes itself */
OSTaskDel(OS_PRIO_SELF);
}
/*
*
* The function 'main' creates only a single task 'StartTask' and starts
* the OS. All other tasks are started from the task 'StartTask'.
*
*/
int main(void) {
printf("Cruise Control 2014\n");
aSemaphore = OSSemCreate(1); // binary semaphore (1 key)
aSemaphore2 = OSSemCreate(0); // binary semaphore (1 key)
OSTaskCreateExt(
StartTask, // Pointer to task code
NULL, // Pointer to argument that is
// passed to task
(void *)&StartTask_Stack[TASK_STACKSIZE-1], // Pointer to top
// of task stack
STARTTASK_PRIO,
STARTTASK_PRIO,
(void *)&StartTask_Stack[0],
TASK_STACKSIZE,
(void *) 0,
OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR);
OSStart();
return 0;
}
輸出：
Cruise Control 2014
delay in ticks 100
SWTimer was created but NOT started
SWTimer was started!
All Tasks and Kernel Objects generated!
Vehicle task created!
SWTimer1 was created but NOT started
SWTimer1 was started!
Control Task created!
Position: 0m
Velocity: 0.4m/s
Throttle: 3V
release key!
released key!
Control Task!
Position: 0m
Velocity: 0.9m/s
Throttle: 4V
release key!
released key!
Control Task!
Position: 0m
Velocity: 1.4m/s
3 個解決方案
解決方案1
1 2014-09-30 09:52:54
OSTimeDlyHMSM()此調用允許您以HOURS，MINUTES，SECONDS和MILLISECONDS而不是刻度來指定延遲時間。 這意味着在適當的時間結束之前，您不會讓任務工作。 即使所有其他任務都工作和/或CPU“免費”，你的任務也不會繼續工作，直到正確的時間滴答，在你的情況下，秒或其他什么都沒有。 如果你真的需要在如此“大”的時間之后發生一件事，那么當然還是值得使用它。
但是，計時器使用的方法不應該與信號量混淆。 后者用於防止數據沖突，並保護共享資源或關鍵代碼段免受多次重入。
如果不深入挖掘您的代碼，我建議盡可能使用OSTimeDly()來組織您的系統。 對於信號量，當您遇到多個任務可以異步調用相同的函數或訪問相同的資源（如內存，寄存器，數據總線或任何硬件）時，請使用它們。
解決方案2
1 已采納 2014-09-30 12:10:53
我的印象是你有兩個你想要定期運行的任務。 並且您希望通過軟件計時器和信號量來實現此目的。 如果這是正確的，那么您可以按如下方式完成此操作。
每個任務都將使用它自己的信號量和計時器。 信號量可以用作發生事件的信號。 在這種情況下，使用信號量指示計時器已過期並且是時間運行任務。 設置軟件定時器以定期過期並調用回調函數。 回調函數應該發布到信號量。 任務應該在while循環中依賴於信號量。 這樣，每當計時器到期時，任務就會循環一次循環。
這是一些偽代碼：
void TimerCallback(params)
{
// Post to the semaphore to signal that it's time to run the task.
}
void TaskFunction(void)
{
// Create a semaphore to represent the "it's time to run" event.
// Initialize the semaphore count to zero because it's not time
// to run yet.
// Create a periodic software timer which calls TimerCallback()
// when it expires.
while(1)
{
// Wait until it's time to run by pending on the semaphore.
// Do task specific stuff.
}
}
此軟件定時器和信號量實現的周期性特性比使用OSTimeDlyHMSM（）更精確。 原因是軟件計時器周期獨立於任務的執行時間而運行。 但是OSTimeDlyHMSM（）的時間段是任務執行時間的補充。 如果任務被其他任務或中斷搶占，則任務的執行時間可能會因迭代而異。 因此，使用OSTimeDlyHMSM（）不是獲取周期性事件的非常精確的方法。
解決方案3
1 2014-10-05 13:39:50
OSTimeDlyHMSM()和OSTimeDly()對於周期性進程的問題在於它們沒有考慮線程其余部分的處理時間。 例如：
// Task loop
for(;;)
{
OSTimeDly( 100 ) ;
doStuffHere() ;
}
你會期望doStuffHere()每100個刻度運行一次， 除非 doStuffHere()本身需要更長的1個刻度周期。 例如，它可能包含延遲或阻止某些其他事件。
// Task loop
for(;;)
{
OSTimeDly( 100 ) ;
doStuffHere() ;
}
通過使用計時器，可以克服：
// Note this is illustrative and not uC/OS-II code
timer_handle = createTimer( 100, PERIODIC ) ;
// Task loop
for(;;)
{
waitForTimer( timer_handle ) ;
doStuffHere() ;
}
在這里， doStuffHere()只需要少於100個滴答來使循環完全周期性 - 這遠遠好於一個滴答。
所有這一切都說如果你能保證 doStuffHere()需要少於一個滴答 - 即使被更高優先級的任務搶占，那么延遲也要簡單得多。
另一方面，使用計時器的另一個優點是延遲上的阻塞只能對延遲的到期作出反應，而阻塞信號量的任務可以對任何給出信號量的事件作出反應，因此可以使其運行包括計時器在內的多個事件。 類似於其他IPC機制，例如隊列或事件標志。
動態C / Rabbit上的Micrium uC-OS / II可能會導致任務缺乏
[英]Micrium uC-OS/II on Dynamic C/Rabbit - might have task starvation
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