EFR32FG12P432F Datasheet, PDF (13/183 Pages) Silicon Laboratories – EFR32FG12 Flex Gecko Proprietary Protocol SoC Family Data Sheet

EFR32FG12 Flex Gecko Proprietary Protocol SoC Family Data Sheet
System Overview
3.6.4 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.
3.6.5 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.
3.6.6 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.
3.6.7 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
3.7.2 Low Energy Universal Asynchronous Receiver/Transmitter (LEUART)
The unique LEUART^TM provides two-way UART communication on a strict power budget. Only a 32.768 kHz clock is needed to allow
UART communication up to 9600 baud. The LEUART includes all necessary hardware to make asynchronous serial communication
possible with a minimum of software intervention and energy consumption.
3.7.3 Inter-Integrated Circuit Interface (I²C)
The I²C module provides an interface between the MCU and a serial I²C bus. It is capable of acting as both a master and a slave and
supports multi-master buses. Standard-mode, fast-mode and fast-mode plus speeds are supported, allowing transmission rates from 10
kbit/s up to 1 Mbit/s. Slave arbitration and timeouts are also available, allowing implementation of an SMBus-compliant system. The
interface provided to software by the I²C module allows precise timing control of the transmission process and highly automated trans-
fers. Automatic recognition of slave addresses is provided in active and low energy modes.
3.7.4 Peripheral Reflex System (PRS)
The Peripheral Reflex System provides a communication network between different peripheral modules without software involvement.
Peripheral modules producing Reflex signals are called producers. The PRS routes Reflex signals from producers to consumer periph-
erals which in turn perform actions in response. Edge triggers and other functionality such as simple logic operations (AND, OR, NOT)
can be applied by the PRS to the signals. The PRS allows peripheral to act autonomously without waking the MCU core, saving power.
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