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 WGM160P 's fea-
tures. 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.
1
2
4
8
6
10
3
5
9
7
12
13
14
11
15
16
17
18
20
19
VMCU
SPI_MOSI / PA0
SPI_MISO / PA1
SPI_SCK / PA2
SPI_CS / PA3
GPIO / PE14
GPIO / PE15
I2C_SDA / PB12
5V
3V3
GND
PB3 / GPIO
PB4 / GPIO
PA4 / GPIO
PA5 / GPIO
PA6 / GPIO
PA15 / GPIO
PB11 / I2C_SCL
BOARD_ID_SDA
BOARD_ID_SCL
Reserved (Board Identification)
WGM160P I/O Pin
Figure 3.3. EXP Header
UG351: WGM160P Wi-Fi Module Wireless Starter Kit User's Guide
Connectors
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