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6174B–ATARM–07-Nov-05
AT91FR40162S Preliminary
17.2
Pin Description
Each USART channel has the following external signals:
Notes:
1. After a hardware reset, the USART pins are not enabled by default (see
”PIO: Parallel I/O Controller” on page 91
must configure the PIO Controller before enabling the transmitter or receiver.
2. If the user selects one of the internal clocks, SCK can be configured as a PIO.
Table 17-1.
Name
Description
SCK
USART Serial clock can be configured as input or output:
SCK is configured as input if an External clock is selected (USCLKS[1] = 1)
SCK is driven as output if the External Clock is disabled (USCLKS[1] = 0) and Clock output is enabled (CLKO = 1)
TXD
Transmit Serial Data is an output
RXD
Receive Serial Data is an input