Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Ficha De Dados
Códigos do produto
ATSAM4E-XPRO
SAM4E [DATASHEET]
Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14
872
37.5.5 Register Write Protection
37.5.6 Test Modes
The UART supports three test modes. These modes of operation are programmed by using the CHMODE field in
UART_MR.
UART_MR.
The automatic echo mode allows bit-by-bit retransmission. When a bit is received on the URXD line, it is sent to
the UTXD line. The transmitter operates normally, but has no effect on the UTXD line.
the UTXD line. The transmitter operates normally, but has no effect on the UTXD line.
The local loopback mode allows the transmitted characters to be received. UTXD and URXD pins are not used
and the output of the transmitter is internally connected to the input of the receiver. The URXD pin level has no
effect and the UTXD line is held high, as in idle state.
and the output of the transmitter is internally connected to the input of the receiver. The URXD pin level has no
effect and the UTXD line is held high, as in idle state.
The remote loopback mode directly connects the URXD pin to the UTXD line. The transmitter and the receiver are
disabled and have no effect. This mode allows a bit-by-bit retransmission.
disabled and have no effect. This mode allows a bit-by-bit retransmission.
Figure 37-11. Test Modes
To prevent any single software error from corrupting UART behavior, certain registers in the
address space can be write-protected by setting the WPEN bit in the
address space can be write-protected by setting the WPEN bit in the
(UART_WPMR).
The following registers can be write-protected:
Receiver
Transmitter
Disabled
RXD
TXD
Receiver
Transmitter
Disabled
RXD
TXD
V
DD
Disabled
Receiver
Transmitter
Disabled
RXD
TXD
Disabled
Automatic Echo
Local Loopback
Remote Loopback
V
DD