Support for Silicon Labs SLTB009A starter kit. More...
Support for Silicon Labs SLTB009A starter kit.
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.
|Vendor Family||EFM32 Giant Gecko 12B|
|Frequency||up to 50 MHz|
|Timers||4x 32-bit, 7x 16-bit + 1x 16-bit (low power)|
|UARTs||2x UART, 5x USART, 1x LEUART|
|Vcc||1.8 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!
| Peripheral | Number | Hardware | Pins | Comments | |---------—|------—|----------------—|--------------------------------—|--------------------------------------------------------—|
|MCU||EFM32GG12B||yes||Power modes supported|
|GPIO||yes||Interrupts are shared across pins (see reference manual)|
|RTCC||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.
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.
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||19 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|
|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_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 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.
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.
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.
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.
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 SLTB009A 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 SLTB009A starter kit. |
|Board specific configuration of direct mapped GPIOs. |
|Configuration of CPU peripherals for the SLTB009A starter kit. |