3.4 Expansion Header
On the right hand side of the Wireless STK Mainboard an angled 20-pin expansion header is provided to allow connection of peripher-
als or plugin boards. The connector contains a number of I/O pins that can be used with most of the EFR32 Mighty Gecko's features.
Additionally, the VMCU, 3V3 and 5V power rails are also exported.
The connector follows a standard which ensures that commonly used peripherals such as an SPI, a UART and an I2C bus are available
on fixed locations in the connector. The rest of the pins are used for general purpose IO. This allows the definition of expansion boards
that can plug into a number of different Silicon Labs Starter Kits.
The figure below shows the pin assignment of the expansion header. Because of limitations in the number of available GPIO pins,
some of the expansion header pins are shared with kit features.
1
2
4
8
6
10
3
5
9
7
12
13
14
11
15
16
17
18
20
19
VMCU
SPI_MOSI / PC6
SPI_MISO / PC7
SPI_CLK / PC8
SPI_CS / PC9
UART_TX / PA0
UART_RX / PA1
I2C_SDA / PC11
5V
3V3
GND
PA2 / GPIO
PA3 / GPIO
PF6 / GPIO
PF7 / GPIO
PF4 / GPIO
PF3 / GPIO
PC10 / I2C_SCL
Board ID SDA
Board ID SCL
Reserved (Board Identification)
EFR32 I/O Pin
Figure 3.3. Expansion Header
UG315: EFR32MG14 2400/868 MHz 13 dBm Dual Band Radio Board User's Guide
Connectors
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