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3.4 EXP Header
The EXP header is an angled, 20-pin expansion header that allows connection of peripherals or plugin boards to the kit. It is located on
the right-hand side of the mainboard and contains several I/O pins that can be used with most of the EFR32 Wireless Gecko's features.
Additionally, the VMCU, 3V3, and 5V power rails are also exposed.
The connector follows a standard which ensures that commonly used peripherals, such as a SPI, a UART, and an I2C bus, are availa-
ble on fixed locations in the connector. The rest of the pins are used for general purpose IO. This allows the definition of expansion
boards (EXP boards) that can plug into several different Silicon Labs Starter Kits.
The figure below shows the pin assignment of the EXP header. Because of limitations in the number of available GPIO pins, some of
the EXP 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 / PC01
SPI_MISO / PC02
SPI_CLK / PC03
SPI_CS / PC00
UART_TX / PA08
UART_RX / PA09
I2C_SDA / PC07
5V
3V3
GND
PB05 / GPIO
PA00 / GPIO
PA05 / GPIO
PD02 / GPIO
PA06 / GPIO
PA07 / GPIO
PC05 / I2C_SCL
BOARD_ID_SDA
BOARD_ID_SCL
Reserved (Board Identification)
EFR32 I/O Pin
Figure 3.5. EXP Header
UG525: EFR32xG24 2.4 GHz 10 dBm Wireless Pro Kit User's Guide
Connectors
silabs.com
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