Support for Silicon Labs STK3700 starter kit. More...
Support for Silicon Labs STK3700 starter kit.
Silicon Labs EFM32 Giant Gecko Starter Kit 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.
|Vendor Family||EFM32 Giant Gecko|
|Frequency||up to 48 MHz|
|Timers||3x 16-bit + 1x 16-bit (low power)|
|ADCs, DACs||12-bit ADC, 12-bit DAC|
|UARTs||2x UART, 3x USART, 2x LEUART|
|Vcc||1.98 V - 3.8 V|
|Board Manual||Board Manual|
|Board Schematic||Can be downloaded using Silicon Labs' Simplicity Studio|
This is the pinout of the expansion header on the right side of the board. PIN 1 is the bottom-left contact when the header faces you horizontally.
Note**: not all starter kits by Silicon Labs share the same pinout!
Note:** some pins are connected to the board controller, when enabled!
|ADC||0||ADC0||CHAN0: internal temperature||Ports are fixed, 14/16-bit resolution not supported|
|DAC||0||DAC0||CHAN0: PB11||Ports are fixed, shared with I2C|
|I2C||0||I2C0||SDA: PD6, SCL: PD7|
|1||I2C1||SDA: PC4, SCL: PC5|
|PWM||0||TIMER3||CHAN0: PE2||Mapped to LED0|
|RTT||—||RTC||Either RTT or RTC (see below)|
|RTC||—||RTC||Either RTC or RTT (see below)|
|SPI||0||USART1||MOSI: PD0, MISO: PD1, CLK: PD2|
|1||USART2||MOSI: NC, MISO: PC3, CLK: PC4|
|Timer||0||TIMER0 + TIMER1||TIMER0 is used as prescaler (must be adjecent)|
|UART||0||UART0||RX: PE1, TX: PE0||STDIO output|
|1||LEUART0||RX: PD5, TX: PD4||Baud rate limited (see below)|
|MCU||EFM32GG||yes||Power modes supported|
|GPIO||yes||Interrupts are shared across pins (see reference manual)|
|RTC||yes||As RTT or RTC|
|SPI||partially||Only master mode|
|UART||yes||USART is shared with SPI. LEUART baud rate limited (see below)|
The starter kit is equipped with a Board Controller. This controller provides a virtual serial port. The board controller is enabled via a GPIO pin.
By default, this pin is enabled. You can disable the board controller module by passing
DISABLE_MODULE=silabs_bc to the
Note:** to use the virtual serial port, ensure you have the latest board controller firmware installed.
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.
This development kit has an Advanced Energy Monitor. It can be connected to the Simplicity Studio development software.
This development kit can measure energy consumption and correlate this with the code. It allows you to measure energy consumption on code-level.
The board controller is responsible for measuring energy consumption. For real-time code correlation, the CoreDebug peripheral will be configured to output MCU register data and interrupt data via the SWO port.
By default, this feature is enabled. It can be disabled by passing
DISABLE_MODULE=silabs_aem to the
Note that Simplicity Studio requires debug symbols to correlate code. RIOT-OS defaults to GDB debug symbols, but Simplicity Studio requires DWARF-2 debug symbols (
-gdwarf-2 for GCC).
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.
|HFRCO||Yes||14 MHz||Enabled during startup, changeable|
|ULFRCO||No||1 kHz||Not very reliable as a time source|
The sources can be used to clock following branches:
|HF||HFRCO, HFXO||Core, peripherals|
|LFA||LFRCO, LFXO||Low-power timers|
|LFB||LFRCO, LFXO, CORELEDIV2||Low-power UART|
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_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.
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.
RIOT-OS has support for Real-Time Tickers and Real-Time Clocks.
However, this board MCU family has support for a 24-bit Real-Time Counter only, which is a ticker only. A compatibility layer for ticker-to-calendar is available, but this includes extra code size to convert from timestamps to time structures and visa versa.
Configured at 1 Hz interval, the RTC will overflow each 194 days. When using the ticker-to-calendar mode, this interval is extended artificially.
This MCUs has support for hardware-accelerated AES128 and AES256.
A peripheral driver interface is proposed, but not yet implemented.
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.
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.
To flash, SEGGER JLink is required.
Flashing is supported by RIOT-OS using the command below:
To run the GDB debugger, use the command:
Or, to connect with your own debugger:
Some boards have (limited) support for emulation, which can be started with:
For using the Silicon Labs STK3700 starter kit we strongly recommend the usage of the GNU Tools for ARM Embedded Processors toolchain.
Silicon Labs' EMLIB: zlib-style license (permits distribution of source).
|Board specific definitions for the STK3700 starter kit. |
|Board specific configuration of direct mapped GPIOs. |
|Configuration of CPU peripherals for the STK3700 starter kit. |