Parts List/Tune Up Info

48
CC2642R
SWRS194G –JANUARY 2018 – REVISED APRIL 2020 www.ti.com
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Detailed Description
Copyright © 2018–2020, Texas Instruments Incorporated
6.7 Timers
A large selection of timers are available as part of the CC2642R device. These timers are:
• Real-Time Clock (RTC)
A 70-bit 3-channel timer running on the 32 kHz low frequency system clock (SCLK_LF)
This timer is available in all power modes except Shutdown. The timer can be calibrated to
compensate for frequency drift when using the LF RCOSC as the low frequency system clock. If an
external LF clock with frequency different from 32.768 kHz is used, the RTC tick speed can be
adjusted to compensate for this. When using TI-RTOS, the RTC is used as the base timer in the
operating system and should thus only be accessed through the kernel APIs such as the Clock
module. The real time clock can also be read by the Sensor Controller Engine to timestamp sensor
data and also has dedicated capture channels. By default, the RTC halts when a debugger halts the
device.
• General Purpose Timers (GPTIMER)
The four flexible GPTIMERs can be used as either 4× 32 bit timers or 8× 16 bit timers, all running on
up to 48 MHz. Each of the 16- or 32-bit timers support a wide range of features such as one-shot or
periodic counting, pulse width modulation (PWM), time counting between edges and edge counting.
The inputs and outputs of the timer are connected to the device event fabric, which allows the timers to
interact with signals such as GPIO inputs, other timers, DMA and ADC. The GPTIMERs are available
in Active and Idle power modes.
• Sensor Controller Timers
The Sensor Controller contains 3 timers:
AUX Timer 0 and 1 are 16-bit timers with a 2
N
prescaler. Timers can either increment on a clock or on
each edge of a selected tick source. Both one-shot and periodical timer modes are available.
AUX Timer 2 is a 16-bit timer that can operate at 24 MHz, 2 MHz or 32 kHz independent of the Sensor
Controller functionality. There are 4 capture or compare channels, which can be operated in one-shot
or periodical modes. The timer can be used to generate events for the Sensor Controller Engine or the
ADC, as well as for PWM output or waveform generation.
• Radio Timer
A multichannel 32-bit timer running at 4 MHz is available as part of the device radio. The radio timer is
typically used as the timing base in wireless network communication using the 32-bit timing word as
the network time. The radio timer is synchronized with the RTC by using a dedicated radio API when
the device radio is turned on or off. This ensures that for a network stack, the radio timer seems to
always be running when the radio is enabled. The radio timer is in most cases used indirectly through
the trigger time fields in the radio APIs and should only be used when running the accurate 48 MHz
high frequency crystal is the source of SCLK_HF.
• Watchdog timer
The watchdog timer is used to regain control if the system operates incorrectly due to software errors.
It is typically used to generate an interrupt to and reset of the device for the case where periodic
monitoring of the system components and tasks fails to verify proper functionality. The watchdog timer
runs on a 1.5 MHz clock rate and cannot be stopped once enabled. The watchdog timer pauses to run
in Standby power mode and when a debugger halts the device.