SAM3A4C Atmel Corporation, SAM3A4C Datasheet - Page 778

• Manufacturer Part Number: SAM3A4C
• Manufacturer: Atmel Corporation

35.6
35.6.1
35.6.2
778
778
Product Dependencies
SAM3X/A
SAM3X/A
I/O Lines
Power Management
The pins used for interfacing the USART may be multiplexed with the PIO lines. The program-
mer must first program the PIO controller to assign the desired USART pins to their peripheral
function. If I/O lines of the USART are not used by the application, they can be used for other
purposes by the PIO Controller.
To prevent the TXD line from falling when the USART is disabled, the use of an internal pull up
is mandatory. If the hardware handshaking feature is used, the internal pull up on TXD must
also be enabled.
Table 35-3.
The USART is not continuously clocked. The programmer must first enable the USART Clock in
the Power Management Controller (PMC) before using the USART. However, if the application
does not require USART operations, the USART clock can be stopped when not needed and be
restarted later. In this case, the USART will resume its operations where it left off.
Configuring the USART does not require the USART clock to be enabled.
Instance
USART0
USART0
USART0
USART0
USART0
USART1
USART1
USART1
USART1
USART1
USART2
USART2
USART2
USART2
USART2
USART3
USART3
USART3
USART3
USART3
I/O Lines
Signal
RXD0
SCK0
RXD1
SCK1
RXD2
SCK2
RXD3
SCK3
CTS0
RTS0
TXD0
CTS1
RTS1
TXD1
CTS2
RTS2
TXD2
CTS3
RTS3
TXD3
I/O Line
PB26
PB25
PB23
PB22
PB21
PB24
PB20
PE16
PA10
PA17
PA11
PA15
PA14
PA12
PA16
PA13
PF4
PF5
PD5
PD4
Peripheral
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12
A
A
A
B
A
A
A
A
A
A
A
A
A
A
A
A
A
B
B
B