EFR32MG-SLTB004A

Overview

The EFR32™ Mighty Gecko Starter Kit EFR32MG-SLTB004A (a.k.a Thunderboard Sense 2) contains a MCU from the EFR32MG family built on ARM® Cortex®-M4F processor with low power capabilities.

Hardware

EFR32MG12 Mighty Gecko Wireless SoC with 38.4 MHz operating frequency
ARM® Cortex® M4 core with 256 kB RAM and 1024 kB Flash
Macronix ultra low power 8-Mbit SPI flash (MX25R8035F)
2.4 GHz ceramic antenna for wireless transmission
Silicon Labs Si7021 relative humidity and temperature sensor
Silicon Labs Si1133 UV index and ambient light sensor
Silicon Labs Si7210 hall effect sensor
Bosch Sensortec BMP280 barometric pressure sensor
ams CCS811 indoor air quality gas sensor
TDK InvenSense ICM-20648 6-axis inertial sensor
TDK InvenSense ICS-43434 MEMS microphone
Four high brightness RGB LEDs from Broadcom Limited (ASMT-YTB7-0AA02)
One bi-color LED and two push buttons
Power enable signals for fine grained power-control
On-board SEGGER J-Link debugger for easy programming and debugging, which includes a USB virtual COM port
Mini Simplicity connector for access to energy profiling and advanced wireless network debugging
Breakout pads for GPIO access and connection to external hardware
Reset button
Automatic switch-over between USB and battery power
CR2032 coin cell holder and external battery connector

For more information about the EFR32MG SoC and Thunderboard Sense 2 (EFR32MG-SLTB004A) board:

Supported Features

The efr32mg_sltb004a board configuration supports the following hardware features:

Interface	Controller	Driver/Component
MPU	on-chip	memory protection unit
NVIC	on-chip	nested vector interrupt controller
SYSTICK	on-chip	systick
COUNTER	on-chip	rtcc
FLASH	on-chip	flash memory
GPIO	on-chip	gpio
UART	on-chip	serial port-polling; serial port-interrupt
I2C	on-chip	i2c port-polling
SPI(M)	on-chip	spi port-polling
WATCHDOG	on-chip	watchdog
TRNG	on-chip	true random number generator

The default configuration can be found in boards/silabs/efr32mg_sltb004a/efr32mg_sltb004a_defconfig

Other hardware features are currently not supported by the port.

Connections and IOs

The EFR32MG SoC has eight gpio controllers (PORTA, PORTB, PORTC, PORTD, PORTF, PORTI, PORTJ and PORTK).

In the following table, the column Name contains Pin names. For example, PE2 means Pin number 2 on PORTE and #27 represents the location bitfield , as used in the board’s and microcontroller’s datasheets and manuals.

Name	Function	Usage
PD8	GPIO	LED0 (RED)
PD9	GPIO	LED1 (GREEN)
PD14	GPIO	SW0 Push Button PB0
PD15	GPIO	Push Button PB1
PA0	UART_TX	UART TX Console VCOM_TX US0_TX #0
PA1	UART_RX	UART RX Console VCOM_RX US0_RX #0
PF3	UART_TX	EXP12_UART_TX LEU0_TX #27
PF4	UART_RX	EXP14_UART_RX LEU0_RX #27
PC10	I2C_SDA	EXP16_I2C_SDA I2C0_SDA #15
PC11	I2C_SCL	EXP15_I2C_SCL I2C0_SCL #15
PB6	I2C_SDA	CCS811_I2C_SDA I2C1_SDA #6
PB7	I2C_SCL	CCS811_I2C_SCL I2C1_SCL #6
PK0	SPI_MOSI	Flash MOSI US2_TX #29
PK2	SPI_MISO	Flash MISO US2_RX #30
PF7	SPI_SCLK	Flash SCLK US2_CLK #18
PK1	SPI_CS	Flash Chip Select (GPIO)

System Clock

The EFR32MG SoC is configured to use the 38.4 MHz external oscillator on the board.

Serial Port

The EFR32MG SoC has four USARTs and one Low Energy UARTs (LEUART with 9600 maximum baudrate). USART0 is configured as the Zephyr console and is connected to the On-Board J-Link Debugger that presents a virtual COM port for general purpose application serial data transfer with this interface.

Programming and Debugging

Note

Before using the kit the first time, you should update the J-Link firmware from J-Link-Downloads

Flashing

The EFR32MG-SLTB004A includes an J-Link serial and debug adaptor built into the board. The adaptor provides:

A USB connection to the host computer, which exposes a Mass Storage and a USB Serial Port.
A Serial Flash device, which implements the USB flash disk file storage.
A physical UART connection which is relayed over interface USB Serial port.

Flashing an application to EFR32-SLTB004A

The sample application Hello World is used for this example. Build the Zephyr kernel and application:

# From the root of the zephyr repository
west build -b efr32mg_sltb004a samples/hello_world

Connect the EFR32MG-SLTB004A to your host computer using the USB port and you should see a USB connection which exposes a Mass Storage (TB004) and a USB Serial Port. Copy the generated zephyr.bin in the SLTB004A drive.

Open a serial terminal (minicom, putty, etc.) with the following settings:

Speed: 115200
Data: 8 bits
Parity: None
Stop bits: 1

Reset the board and you should be able to see on the corresponding Serial Port the following message:

Hello World! arm