User's Manual

Silicon Laboratories Finland Oy
Page 9 of 51
UART signal
Pad number
Pad type
Description
UART_TX
26
Output, weak internal
pull-up
UART data output, active
high
UART_RTS#
5
Output, weak internal
pull-up
UART request to send,
active low
UART_RX
6
Input, weak internal pull-
down
UART data input, active
high
UART_CTS#
10
Input, weak internal pull-
down
UART clear to send,
active low
Table 5: UART Terminal Descriptions
USB signal
Pad number
Pad type
Description
USB+
8
Bidirectional
USB data line with internal 1.5kohm pull-up
USB-
9
Bidirectional
USB data line
Table 6: USB Terminal Descriptions
SPI signal
Pad
number
Pad type
Description
SPI_MOSI
24
Input, weak internal pull-down
SPI data input
SPI_CS#
21
Input, weak internal pull-up
Chip select, active low
SPI_CLK
22
Input, weak internal pull-down
SPI clock
SPI_MISO
23
Output, weak internal pull-down
SPI data output
Table 7: Terminal Descriptions