Exp Header - Silicon Laboratories EFR32xG21B User Manual

3.4 EXP Header

The EXP header is an angled 20-pin expansion header provided to allow connection of peripherals or plugin boards to the kit. It is loca-
ted on the right-hand side of the mainboard, and it contains a number of 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 exported.
The connector follows a standard which ensures that commonly used peripherals, such as an 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 a number of 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.
silabs.com | Building a more connected world.
3V3 20
5V 18
NC 16
UART_RX / PA06 14
UART_TX / PA05
12
SPI_CS / PC03 10
8
SPI_CLK / PC02
SPI_MISO / PC01 6
SPI_MOSI / PC00 4
VMCU 2
EFR32 I/O Pin
Reserved (Board Identification)
Figure 3.3. EXP Header
UG428: EFR32xG21B 2.4 GHz 10 dBm Wireless Starter Kit User's Guide
19 BOARD_ID_SDA
17 BOARD_ID_SCL
15 NC
13 PD03 / GPIO
11 PD02 / GPIO
9 PB01 / GPIO
7
PB00 / GPIO
5 NC
3 NC
1 GND
Connectors
Rev. 1.0 | 9