Zephyr Project Requirements
Timers

Timers

 STATEMENT:

SPDX-License-Identifier: Apache-2.0
1. Timer definition at compile time
UID: ZEP-SRS-4-1
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall provide a mechanism to define and statically (i.e. compile time) initialize timers.
2. Timer expiry function
UID: ZEP-SRS-4-2
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

When initializing a timer, the Zephyr RTOS shall support setting a function that gets called when the timer expires.
3. Timer stop function
UID: ZEP-SRS-4-3
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

When initializing a timer, the Zephyr RTOS shall support setting a function that gets called when a running timer is stopped.
4. Timer definition at run time
UID: ZEP-SRS-4-4
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall provide a mechanism to define and initialize timers at run time.
5. Timer start
UID: ZEP-SRS-4-5
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall provide a mechanism to start a timer for a specific duration and periodicity.
6. Timer stop
UID: ZEP-SRS-4-6
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall provide a mechanism to stop a running timer.
7. Timer status
UID: ZEP-SRS-4-7
STATUS: Draft
TYPE: Non-Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall provide a mechanism to read the number of times a timer has expired and then reset this number to 0.
8. Timer status reinitialization
UID: ZEP-SRS-4-8
STATUS: Draft
TYPE: Non-Functional
COMPONENT: Timers
parent relations: STATEMENT:

When a timer is initialized, started or synchronized to a thread, the Zephyr RTOS shall reset the timer number of times it has expired to 0.
9. Timer thread synchronization
UID: ZEP-SRS-4-9
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall provide a mechanism to synchronize a thread to a timer and then block the thread execution until any of the following conditions is satisfied: - The timer is stopped - The timer number of times it has expired is superior to 0
10. Timer next expiration time in system ticks
UID: ZEP-SRS-4-10
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall provide a mechanism to get a timer's next expiration time in system ticks.
11. Timer remaining time until expiration in system ticks
UID: ZEP-SRS-4-11
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall provide a mechanism to get a timer's remaining time until its next expiry in system ticks.
12. Timer remaining time until expiration in milliseconds
UID: ZEP-SRS-4-12
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall provide a mechanism to get the timer's remaining time until its next expiry in milliseconds.
13. Timer set user data
UID: ZEP-SRS-4-13
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall support adding user defined data to a timer.
14. Timer get user data
UID: ZEP-SRS-4-14
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

The Zephyr RTOS shall support retrieving user defined data from a timer.
15. Timer expire functions in interrupt context
UID: ZEP-SRS-4-15
STATUS: Draft
TYPE: Functional
COMPONENT: Timers
parent relations: STATEMENT:

When a timer expiry function is called, the Zephyr RTOS shall do so in the interrupt context.