Atmel SAM4S Series, Предварительный информационный лист

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711
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
33.4 Product Dependencies
33.4.1 I/O Lines
The UART pins are multiplexed with PIO lines. The programmer must first configure the corre-
sponding PIO Controller to enable I/O line operations of the UART.
33.4.2 Power Management
The UART clock is controllable through the Power Management Controller. In this case, the pro-
grammer must first configure the PMC to enable the UART clock. Usually, the peripheral
identifier used for this purpose is 1.
33.4.3 Interrupt Source
The UART interrupt line is connected to one of the interrupt sources of the Nested Vectored
Interrupt Controller (NVIC). Interrupt handling requires programming of the NVIC before config-
uring the UART.
33.5 UART Operations
The UART operates in asynchronous mode only and supports only 8-bit character handling (with
parity). It has no clock pin.
The UART is made up of a receiver and a transmitter that operate independently, and a common
baud rate generator. Receiver timeout and transmitter time guard are not implemented. How-
ever, all the implemented features are compatible with those of a standard USART.
33.5.1 Baud Rate Generator
The baud rate generator provides the bit period clock named baud rate clock to both the receiver
and the transmitter.
The baud rate clock is the master clock divided by 16 times the value (CD) written in
UART_BRGR (Baud Rate Generator Register). If UART_BRGR is set to 0, the baud rate clock is
disabled and the UART remains inactive. The maximum allowable baud rate is Master Clock
divided by 16. The minimum allowable baud rate is Master Clock divided by (16 x 65536).
Table 33-2. I/O Lines
Instance Signal I/O Line Peripheral
UART0 URXD0 PA9 A
UART0 UTXD0 PA10 A
UART1 URXD1 PB2 A
UART1 UTXD1 PB3 A
Baud Rate
MCK
16 CD
×
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