Data Sheet

Silicon Labs
Page 18 of 45
6.3 I
2
C/SPI
Pad number I
2
C SPI
17 SS4 – Slave select SPI 4
19 SCK4 - Clock SPI 4
29 SCL3 – Clock I
2
C 3 SDO3 – Data out SPI 3
32 SDA3 – Data I
2
C 3 SDI3 – Data in SPI 3
35 SDA5 – Data I
2
C 5 SDI4 – Data in SPI 4
36 SCL5 – Clock I
2
C 5 SDO4 – Data out SPI 4
44 SDA1 – Data I
2
C 1 SS3 – Slave select SPI 3
46 SCL1 – Clock I
2
C 1
47 SCK3 – Clock SPI 3
Table 4: Pads for I2C and SPI
Up to three I
2
C-ports and up to two SPI ports can be implemented, mostly multiplexed on the same pins
together and with the UART signals. The I
2
C ports support 100 kHz and 400 kHz speed specifications
including automatic clock stretching, while the SPI can be operated at up to 20 Mbps. The SPI ports are also
available for use as a host connection for use with an external microcontroller. The SPI bus can be configured
for any clock phase combination.
For details on the SPI/I2C hardware, please refer to Microchip documentation on SPI and I2C
.
To see what other functions are present on the same pins, please refer to Table 2.
6.4 USB
Pad number Function Description
18 OTG_ID USB-OTG mode identify line (not used)
25 VBUS USB bus supply input
27 D- Data -
28 D+ Data +
24 VBUSON USB bus supply switch enable (not used)
Table 5: USB pads
The module contains a USB-OTG system with an integrated transceiver. Full Speed (12 Mbps) USB 2.0
standard is supported in device mode. The current firmware has no support for the host mode.
Using the USB connection requires an external crystal on OSC1/OSC2 for sufficient clock accuracy.