Generic Wait Functions

Wait for a certain period of time. More...

Functions
osStatus_t	osDelay (uint32_t ticks)
	Wait for Timeout (Time Delay). More...
osStatus_t	osDelayUntil (uint64_t ticks)
	Wait until specified time. More...

Description

The generic wait functions provide means for a time delay.

Note

Generic wait functions cannot be called from Interrupt Service Routines.

Function Documentation

osStatus_t osDelay

(

uint32_t

ticks

)

Parameters

[in]

ticks

time ticks value

Returns

status code that indicates the execution status of the function.

The function osDelay waits for a time period specified in kernel ticks. For a value of 1, the system waits until the next timer tick occurs. That means that the actual time delay may be up to one timer tick less.

Possible osStatus_t return values:

• osOK: the time delay is executed.
• osErrorISR: osDelay cannot be called from Interrupt Service Routines.

Note

This function cannot be called from Interrupt Service Routines.

Code Example

#include "cmsis_os2.h"
 
void Thread_1 (void *arg)  {                // Thread function
  osStatus_t status;                        // capture the return status
  uint32_t   delayTime;                     // delay time in milliseconds
 
  delayTime = 1000;                         // delay 1 second
  status = osDelay (delayTime);             // suspend thread execution
}

osStatus_t osDelayUntil

(

uint64_t

ticks

)

Parameters

[in]

ticks

absolute time in ticks

Returns

status code that indicates the execution status of the function.

The function osDelayUntil waits until an absolute time (specified in kernel ticks) is reached.

Possible osStatus_t return values:

• osOK: the time delay is executed.
• osParameter: the time is either in the past or cannot be handled (out of bounds).
• osErrorISR: osDelayUntil cannot be called from Interrupt Service Routines.

Note

This function cannot be called from Interrupt Service Routines.

Code Example

#include "cmsis_os2.h"
 
void Thread_1 (void *arg)  {                // Thread function
  uint64_t tick;

  tick = osKernelGetTickCount();            // retrieve the number of system ticks
  for (;;) {
    tick += 1000;                           // delay 1000 ticks periodically
    osDelayUntil(tick);
    // ...
  }
}