SLWSTK6020A Datasheet, PDF (9/102 Pages) Silicon Laboratories – EFR32BG1 Blue Gecko Bluetooth® Smart SoC Family Data Sheet

3.6 Counters/Timers and PWM
EFR32BG1 Blue Gecko Bluetooth® Smart SoCFamily Data Sheet
System Overview
3.6.1 Timer/Counter (TIMER)
TIMER peripherals keep track of timing, count events, generate PWM outputs and trigger timed actions in other peripherals through the
PRS system. The core of each TIMER is a 16-bit counter with up to 4 compare/capture channels. Each channel is configurable in one
of three modes. In capture mode, the counter state is stored in a buffer at a selected input event. In compare mode, the channel output
reflects the comparison of the counter to a programmed threshold value. In PWM mode, the TIMER supports generation of pulse-width
modulation (PWM) outputs of arbitrary waveforms defined by the sequence of values written to the compare registers, with optional
dead-time insertion available in timer unit TIMER_0 only.
3.6.2 Real Time Counter and Calendar (RTCC)
The Real Time Counter and Calendar (RTCC) is a 32-bit counter providing timekeeping in all energy modes. The RTCC includes a
Binary Coded Decimal (BCD) calendar mode for easy time and date keeping. The RTCC can be clocked by any of the on-board oscilla-
tors with the exception of the AUXHFRCO, and it is capable of providing system wake-up at user defined instances. When receiving
frames, the RTCC value can be used for timestamping. The RTCC includes 128 bytes of general purpose data retention, allowing easy
and convenient data storage in all energy modes.
3.6.3 Low Energy Timer (LETIMER)
The unique LETIMER is a 16-bit timer that is available in energy mode EM2 Deep Sleep in addition to EM1 Sleep and EM0 Active. This
allows it to be used for timing and output generation when most of the device is powered down, allowing simple tasks to be performed
while the power consumption of the system is kept at an absolute minimum. The LETIMER can be used to output a variety of wave-
forms with minimal software intervention. The LETIMER is connected to the Real Time Counter and Calendar (RTCC), and can be con-
figured to start counting on compare matches from the RTCC.
3.6.4 Ultra Low Power Wake-up Timer (CRYOTIMER)
The CRYOTIMER is a 32-bit counter that is capable of running in all energy modes. It can be clocked by either the 32.768 kHz crystal
oscillator (LFXO), the 32.768 kHz RC oscillator (LFRCO), or the 1 kHz RC oscillator (ULFRCO). It can provide periodic Wakeup events
and PRS signals which can be used to wake up peripherals from any energy mode. The CRYOTIMER provides a wide range of inter-
rupt periods, facilitating flexible ultra-low energy operation.
3.6.5 Pulse Counter (PCNT)
The Pulse Counter (PCNT) peripheral can be used for counting pulses on a single input or to decode quadrature encoded inputs. The
clock for PCNT is selectable from either an external source on pin PCTNn_S0IN or from an internal timing reference, selectable from
among any of the internal oscillators, except the AUXHFRCO. The module may operate in energy mode EM0 Active, EM1 Sleep, EM2
Deep Sleep, and EM3 Stop.
3.6.6 Watchdog Timer (WDOG)
The watchdog timer can act both as an independent watchdog or as a watchdog synchronous with the CPU clock. It has windowed
monitoring capabilities, and can generate a reset or different interrupts depending on the failure mode of the system. The watchdog can
also monitor autonomous systems driven by PRS.
3.7 Communications and Other Digital Peripherals
3.7.1 Universal Synchronous/Asynchronous Receiver/Transmitter (USART)
The Universal Synchronous/Asynchronous Receiver/Transmitter is a flexible serial I/O module. It supports full duplex asynchronous
UART communication with hardware flow control as well as RS-485, SPI, MicroWire and 3-wire. It can also interface with devices sup-
porting:
• ISO7816 SmartCards
• IrDA
• _I²_S
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