Silicon Labs SLTB009A starter kit

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When using this board with RIOT, set the BOARD variable to sltb009a in your Makefile. If you follow the standard RIOT project structure, your Makefile should look like this:

# name of your application
APPLICATION = hello-world

# Change this to your board if you want to build for a different board
BOARD ?= sltb009a

# This has to be the absolute path to the RIOT base directory:
RIOTBASE ?= $(CURDIR)/RIOT

include $(RIOTBASE)/Makefile.include

Support for Silicon Labs SLTB009A starter kit

Overview

Silicon Labs Thunderboard GG12 is equipped with the EFM32 microcontroller. It is specifically designed for low-power applications, having energy-saving peripherals, different energy modes and short wake-up times.

The starter kit is equipped with an Advanced Energy Monitor. This allows you to actively measure the power consumption of your hardware and code, in real-time.

Hardware

MCU

MCU	EFM32GG12B810F1024GM64
Family	ARM Cortex-M4F
Vendor	Silicon Labs
Vendor Family	EFM32 Giant Gecko 12B
RAM	192.0 KiB
Flash	1024.0 KiB
EEPROM	no
Frequency	up to 50 MHz
FPU	yes
MPU	yes
DMA	12 channels
Timers	4 x 32-bit, 7 x 16-bit + 1 x 16-bit (low power)
ADCs	12-bit ADC
DACs	2 x 12-bit VDAC (500 ksamples/s), 1 x IDAC
I2Cs	2 x
SPIs	5 x USART
UARTs	2 x UART, 5 x USART, 1 x LEUART
USB	1 x Low Energy Full-Speed USB 2.0
Vcc	1.8 V - 3.8 V
Datasheet	Datasheet
Manual	Manual
Board Manual	Board Manual
Board Schematic	Can be downloaded using Silicon Labs’ Simplicity Studio

Pinout

This is the pinout of the expansion header of the board. PIN 1 is the top-left contact.

RIOT Peripheral	Name	PIN	PIN	Name	RIOT Peripheral
	GND	1	2	VMCU
	PD0	3	4	PA0	SPI_DEV(0):MOSI
	PD1	5	6	PA1	SPI_DEV(0):MISO
	PA4	7	8	PA2	SPI_DEV(0):CLK
	PA5	9	10	PA3
	PA6	11	12	PC4	UART_DEV(1):TX
	PE15	13	14	PC5	UART_DEV(1):RX
I2C_DEV(0):SCL	PE5	15	16	PE4	I2C_DEV(0):SCL
		17	18	5V
		19	20	3V3
	PB12	21	22	PE8
DAC_LINE(0)	PB11	23	24	PE9
	PB3	25	26	PE10
	PB4	27	28	PE11
	PD2	29	30	PE13
	PD3	31	32	PE14
	PD4	33	34	PF5

Peripheral mapping

Peripheral	Number	Hardware	Pins	Comments
ADC	0	ADC0:CH0		Internal temperature
ADC	1	ADC0:CH1		AVDD
I2C	0	I2C0	SDA:PE4, SCL:PE5	Normal speed
HWCRYPTO	-	-		AES128/AES256, SHA1, SHA224/SHA256
HWRNG	-	TNRG0		True Random Number Generator (TRNG)
RTT	-	RTCC		1 Hz interval, either RTT or RTC
RTC	-	RTCC		1 Hz interval, either RTT or RTC
SPI	0	USART3	MOSI:PA0, MISO:PA1, CLK:PA2
Timer	0	WTIMER0 + WTIMER1		WTIMER0 is used as prescaler
Timer	1	TIMER0 + TIMER1		TIMER0 is used as prescaler
Timer	2	LETIMER0
UART	0	USART0	RX:PE6, TX:PE7	Default STDIO
UART	1	UART0	RX:PC5, TX:PC4

User interface

Peripheral	Mapped to	Pin
Button	PB0_PIN	PD5
	PB1_PIN	PD8
LED	LED0R_PIN	PA12
	LED0G_PIN	PA13
	LED0B_PIN	PA14
	LED1R_PIN	PD6
	LED1G_PIN	PF12
	LED1B_PIN	PE12
	LED0_PIN	LED0R_PIN
	LED1_PIN	LED1R_PIN

Implementation Status

Device	ID	Supported	Comments
MCU	EFM32GG12B	yes	Power modes supported
Low-level driver	ADC	yes
	DAC	yes	VDAC, IDAC is not supported
	Flash	yes
	GPIO	yes	Interrupts are shared across pins (see ref manual)
	HW Crypto	yes
	I2C	yes
	PWM	yes
	RTCC	yes	As RTT or RTC
	SPI	yes	Only master mode
	Timer	yes
	UART	yes	USART is shared with SPI. LEUART baud rate limited
	USB	yes	Device mode

Board configuration

Board controller

The starter kit is equipped with a Board Controller. This controller provides a virtual serial port.

Note: the board controller always configures the virtual serial port at 115200 baud with 8 bits, no parity and one stop bit. This also means that it expects data from the MCU with the same settings.

Clock selection

There are several clock sources that are available for the different peripherals. You are advised to read AN0004.0 to get familiar with the different clocks.

Source	Internal	Speed	Comments
HFRCO	Yes	19 MHz	Enabled during startup, changeable
HFXO	No	50 MHz
LFRCO	Yes	32.768 kHz
LFXO	No	32.768 kHz
ULFRCO	No	1 kHz	Not very reliable as a time source

The sources can be used to clock following branches:

Branch	Sources	Comments
HF	HFRCO, HFXO	Core, peripherals
LFA	LFRCO, LFXO	Low-power timers
LFB	LFRCO, LFXO, CORELEDIV2	Low-power UART
LFE	LFRCO, LFXO	Real-time Clock and Calendar

CORELEDIV2 is a source that depends on the clock source that powers the core. It is divided by 2 or 4 to not exceed maximum clock frequencies (EMLIB takes care of this).

The frequencies mentioned in the tables above are specific for this starter kit.

It is important that the clock speeds are known to the code, for proper calculations of speeds and baud rates. If the HFXO or LFXO are different from the speeds above, ensure to pass EFM32_HFXO_FREQ=freq_in_hz and EFM32_LFXO_FREQ=freq_in_hz to your compiler.

You can override the branch’s clock source by adding CLOCK_LFA=source to your compiler defines, e.g. CLOCK_LFA=cmuSelect_LFRCO.

Low-power peripherals

The low-power UART is capable of providing an UART peripheral using a low-speed clock. When the LFB clock source is the LFRCO or LFXO, it can still be used in EM2. However, this limits the baud rate to 9600 baud. If a higher baud rate is desired, set the clock source to CORELEDIV2.

Note: peripheral mappings in your board definitions will not be affected by this setting. Ensure you do not refer to any low-power peripherals.

RTC or RTT

RIOT-OS has support for Real-Time Tickers and Real-Time Clocks.

However, this board MCU family has support for a 32-bit Real-Time Clock and Calendar, which can be configured in ticker mode or calendar mode. Therefore, only one of both peripherals can be enabled at the same time.

Configured at 1 Hz interval, the RTCC will overflow each 136 years.

Hardware crypto

This MCU is equipped with a hardware-accelerated crypto peripheral that can speed up AES128, AES256, SHA1, SHA256 and several other cryptographic computations.

A peripheral driver interface is proposed, but not yet implemented.

Usage of EMLIB

This port makes uses of EMLIB by Silicon Labs to abstract peripheral registers. While some overhead is to be expected, it ensures proper setup of devices, provides chip errata and simplifies development. The exact overhead depends on the application and peripheral usage, but the largest overhead is expected during peripheral setup. A lot of read/write/get/set methods are implemented as inline methods or macros (which have no overhead).

Another advantage of EMLIB are the included assertions. These assertions ensure that peripherals are used properly. To enable this, pass DEBUG_EFM to your compiler.

Pin locations

The EFM32 platform supports peripherals to be mapped to different pins (predefined locations). The definitions in periph_conf.h mostly consist of a location number and the actual pins. The actual pins are required to configure the pins via GPIO driver, while the location is used to map the peripheral to these pins.

In other words, these definitions must match. Refer to the data sheet for more information.

This MCU has extended pin mapping support. Each pin of a peripheral can be connected separately to one of the predefined pins for that peripheral.

Flashing the device

The board provides a on-board J-Link debugger through the micro USB board so that flashing and debugging is very easy.

Flashing is supported by RIOT-OS using the command below:

make flash

To run the GDB debugger, use the command:

make debug

Or, to connect with your own debugger:

make debug-server

Some boards have (limited) support for emulation, which can be started with:

make emulate

Supported Toolchains

For using the Silicon Labs SLTB009A starter kit we strongly recommend the usage of the GNU Tools for ARM Embedded Processors toolchain.

License information

Silicon Labs’ EMLIB: zlib-style license (permits distribution of source).