Timers¶

This section is aimed to provide users an overview on available timers, timer usage, and availability across various power states.

Table 2. Timer Overview¶
Timer	Availability in Power Mode	Resolution
General Purpose Timer	Available in Active mode and Idle mode.	(1/48)us
Watchdog Timer	Available in Active mode, Idle mode, and Standby mode.	(1/32)us
System Timer	Available in Active mode and Idle mode.	1us or 250ns
Real-Time Clock	Available in Active mode, Idle mode, and Standby mode.	8us or 524ms
Clock DPL	Available in Active mode, Idle mode, and Standby mode.	1us
FreeRTOS Timer	Available in Active mode and Idle mode.	10ms

Hardware Timers¶

There are 4 types of HW timer available for the application to use.

General Purpose Timer (LGPT)¶

The General Purpose Timer (LGPT) runs off of the 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.

Watchdog Timer¶

The Watchdog Timer is used as a recovery mechanism to regain control. Upon timer expiration, the CC23xx will be reset. Because the CC23xx behaves differently than previous generations, a workaround is needed to reduce the power consumption of the Watchdog Timer. The Watchdog Timer Example Code explains this workaround.

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 the CC23xx’s future wake up time before going into Standby mode.

System Timer (SYSTIM)¶

SYSTIM has 5 channels; 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 Timers¶

ClockP Module¶

The ClockP module is developed by Texas Instruments and uses one SYSTIM channel with 1 us resolution and is synchronized with the 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

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