Timers¶
This section is aimed to provide users an overview on available timers, timer usage and availability across various power states.
Timer |
Availability in Power Mode |
Resolution |
|---|---|---|
General Purpose Timer |
Available in Active mode and Idle mode |
(1/48)MHz |
Watchdog Timer |
Available in Active mode, Idle mode and Standby mode. |
|
System Timer |
Available in Active mode, Idle mode. |
1us or 250ns |
Real-Time Clock |
Available in Active mode, Idle mode and Standby mode. |
8us |
Clock DPL |
Available in Active mode, Idle mode and Standby mode. |
1us |
FreeRTOS Timer |
Available in Active mode, Idle mode. |
10ms |
Hardware Timer¶
There are 4 HW timers available for the application to use.
General Purpose Timer (LGPT)¶
The General Purpose Timer (LGPT) runs off on High Frequency Clock which is only available in Active or Idle mode. LGPT is often used for high accuracy measurement, timer comparison, DMA triggering, PWM, etc. For more information, please refer to the CC23xx datasheet.
Note
The General Purpose Timer driver is not yet available.
Watchdog Timer¶
The Watchdog timer is used as a recovery mechanism to regain control. Upon timer expiration, the CC23xx will be reset.
Note
The watchdog Timer driver is not yet available.
Real-Time Clock (RTC)¶
The RTC is a 2-channel timer (compare channel and capture channel) and runs on the Low Frequency Clock. The compare channel is used by system software to program CC23xx future wake up time before going into Standby mode.
System Timer (SYSTIM)¶
SYSTIM has 5 channels and 4 channels are reserved by system software and radio operation. There is only one available for the user. SYSTIM is synchronized to RTC in hardware.
To get current device timestamp, users should use ClockP_getSystemTicks() from ClockP Module
Attention
For more Hardware Timer information, please refer to the CC23xx datasheet. In general, it is recommended to use ClockP Module if users want to realize the functionality provided by SYSTIM.
Software Timer¶
ClockP Module¶
The ClockP module is developed by Texas Instruments and uses one SYSTIM channel with 1 us resolution and is synchronized with RTC.
ClockP can be used to do the following:
Get current timestamp
Get CPU clock frequency
Periodic timer to trigger periodic task
One shot timer to trigger task
Note
Currently there is no API documentation available for this module.
To see the available APIs, please navigate to
<SDK_INSTALL_DIR>/source/ti/drivers/dpl/ClockP.h
FreeRTOS Timer¶
FreeRTOS has its own timer module. For more information, please refer to: FreeRTOS Software Timers