Wiring OS API
Wiring OS API
Description
A wrapper to CMSIS (Cortex Microcontroller Software Interface Standard) OS API which serves as an RTOS to create the multi-threaded application with real-time behavior.
Syntax
NA
Members
| Public Methods | |
| os_thread_create | Create a thread and add it to Active Threads and set it to state READY |
| os_thread_get_id | Return the thread ID of the current running thread |
| os_thread_terminate | Terminate execution of a thread and remove it from Active Threads |
| os_thread_yield | Pass control to next thread that is in state READY |
| os_thread_set_priority | Change priority of an active thread |
| os_thread_get_priority | Get current priority of an active thread |
| os_signal_set | Set the specified Signal Flags of an active thread |
| os_signal_clear | Clear the specified Signal Flags of an active thread |
| os_signal_wait | Wait for one or more Signal Flags to become signaled for the current RUNNING thread |
| os_timer_create | Create a timer |
| os_timer_start | Start or restart a timer |
| os_timer_stop | Stop the timer |
| os_timer_delete | Delete a timer that was created by os_timer_create |
| os_semaphore_create | Create and Initialize a Semaphore object used for managing resources |
| os_semaphore_wait | Wait until a Semaphore token becomes available |
| os_semaphore_release | Release a Semaphore token |
| os_semaphore_delete | Delete a Semaphore that was created by os_semaphore_create |
| os_get_free_heap_size | Return the available heap memory space when called |
os_thread_create
Description
Create a thread and add it to Active Threads and set it to state READY.
Syntax
uint32_t os_thread_create(void (*task)(const void *argument), void *argument, int priority, uint32_t stack_size);
Parameters
task: task Function pointer which is the thread body. It should not run into the end of function unless os_thread_terminate is invoked
argument: the data pointer which brings to task
priority: The underlying os is FreeRTOS. It executes tasks with highest priority which are not in idle state.
stack_size: The stack_size is used as memory heap only for this task.
Returns
The thread id which is used in thread operation and signalling.
Example Code
NA
Notes and Warnings
NA
os_thread_get_id
Description
Return the thread ID of the current running thread
Syntax
uint32_t os_thread_get_id(void);
Parameters
The function requires no input parameter.
Returns
Current thread id which calls os_thread_get_id.
Example Code
NA
Notes and Warnings
NA
os_thread_terminate
Description
Terminate execution of a thread and remove it from Active Threads
Syntax
uint32_t os_thread_terminate(uint32_t thread_id);
Parameters
thread_id: Terminate the thread with specific thread_id
Returns
os_status code
Example Code
NA
Notes and Warnings
Thread should not ended without terminate first.
os_thread_yield
Description
Pass control to next thread that is in state READY
Syntax
uint32_t os_thread_yield(void);
Parameters
The function requires no input parameter.
Returns
os_status code
Example Code
NA
Notes and Warnings
By default, the minimal execution unit is 1 millisecond. In a scenario that if a thread with smaller want to handout execution right to a thread with higher priority immediately without waiting for the ending of current 1 millisecond, then invoke os_thread_yield can transfer exection right to OS’s idle task and check which is the next execution thread.
os_thread_set_priority
Description
Change priority of an active thread
Syntax
uint32_t os_thread_set_priority(uint32_t thread_id, int priority);
Parameters
thread_id: The target thread with the thread id to be changed
priority: The updated priority
Returns
The function returns nothing.
Example Code
NA
Notes and Warnings
NA
os_thread_get_priority
Description
Get current priority of an active thread
Syntax
uint32_t os_thread_get_priority(uint32_t thread_id);
Parameters
thread_id: The target thread with the thread id to be searched
Returns
os_priority
Example Code
NA
Notes and Warnings
NA
os_signal_set
Description
Set the specified Signal Flags of an active thread
Syntax
int32_t os_signal_set(uint32_t thread_id, int32_t signals);
Parameters
thread_id: Send signal to a thread with the thread id
signals: the signals to be send
Returns
os_status code
Example Code
NA
Notes and Warnings
NA
os_signal_clear
Description
Clear the specified Signal Flags of an active thread
Syntax
int32_t os_signal_clear(uint32_t thread_id, int32_t signals);
Parameters
thread_id: Clear signal to a thread with the thread id
signals: The signals to be clear
Returns
os_status code
Example Code
NA
Notes and Warnings
NA
os_signal_wait
Description
Wait for one or more Signal Flags to become signaled for the current RUNNING thread
Syntax
os_event_t os_signal_wait(int32_t signals, uint32_t millisec);
Parameters
signals: the signals to be wait
millisec: the timeout value if no signal comes in. Fill in 0xFFFFFFFF for infinite wait
Returns
os_status code
Example Code
NA
Notes and Warnings
NA
os_timer_create
Description
Create a timer
Syntax
uint32_t os_timer_create(void (*callback)(void const *argument), uint8_t isPeriodic, void *argument);
Parameters
callback: The function to be invoke when timer timeout
isPeriodic: OS_TIMER_ONCE or OS_TIMER_PERIODIC
argument: The argument that is bring into callback function
Returns
timer id
Example Code
NA
Notes and Warnings
NA
os_timer_start
Description
Start or restart a timer
Syntax
uint32_t os_timer_start(uint32_t timer_id, uint32_t millisec);
Parameters
timer_id: The timer id obtained from by os_timer_create
millisec: The delays after timer starts
Returns
os_status code
Example Code
NA
Notes and Warnings
NA
os_timer_stop
Description
Stop the timer
Syntax
uint32_t os_timer_stop(uint32_t timer_id);
Parameters
timer_id: The timer id obtained from by os_timer_create
Returns
os_status code
Example Code
NA
Notes and Warnings
NA
os_timer_delete
Description
Delete a timer that was created by os_timer_create
Syntax
uint32_t os_timer_delete(uint32_t timer_id);
Parameters
timer_id: The timer id obtained from by os_timer_create
Returns
os_status code
Example Code
NA
Notes and Warnings
NA
os_semaphore_create
Description
Create and Initialize a Semaphore object used for managing resources
Syntax
uint32_t os_semaphore_create(int32_t count);
Parameters
count: The number of available resources
Returns
semaphore ID
Example Code
NA
Notes and Warnings
NA
os_semaphore_wait
Description
Wait until a Semaphore token becomes available
Syntax
int32_t os_semaphore_wait(uint32_t semaphore_id, uint32_t millisec);
Parameters
semaphore_id: semaphore id obtained from os_semaphore_create
millisec: timeout value
Returns
os_status code
Example Code
NA
Notes and Warnings
NA
os_semaphore_release
Description
Release a Semaphore token
Syntax
uint32_t os_semaphore_release(uint32_t semaphore_id);
Parameters
semaphore_id: semaphore id obtained from os_semaphore_create
Returns
os_status code
Example Code
NA
Notes and Warnings
NA
os_semaphore_delete
Description
Delete a Semaphore that was created by os_semaphore_create
Syntax
uint32_t os_semaphore_delete(uint32_t semaphore_id);
Parameters
semaphore_id: semaphore id obtained from os_semaphore_create
Returns
os_status code
Example Code
NA
Notes and Warnings
NA
os_get_free_heap_size
Description
Return the available heap memory space when called
Syntax
size_t os_get_free_heap_size(void);
Parameters
The function requires no input parameter.
Returns
The function returns the current free heap size
Example Code
Example: MemInfo
This example shows how to get the free heap size of the current OS. The heap is meant for memory to allocate and creating the thread. If the heap size is too low, then some function may behave abnormally from the failure of the memory allocation.
void setup() {
char *buf;
Serial.print("Dynamic memory size: ");
Serial.println(os_get_free_heap_size());
Serial.println();
buf = (char *) malloc ( 1000 );
Serial.println("Allocate 1000 bytes");
Serial.print("Dynamic memory size: ");
Serial.println(os_get_free_heap_size());
Serial.println();
free(buf);
Serial.println("Free 1000 bytes");
Serial.print("Dynamic memory size: ");
Serial.println(os_get_free_heap_size());
}
void loop() {
delay(1000);
}
Notes and Warnings
NA
