Datasheet

SAM9261 [DATASHEET]
Atmel-6062O-ATARM-SAM9261-Datasheet_21-Jun-16
450
31.6.4.7 Protocol T = 1
When operating in ISO7816 protocol T = 1, the transmission is similar to an asynchronous format with only one
stop bit. The parity is generated when transmitting and checked when receiving. Parity error detection sets the
PARE bit in the Channel Status Register (US_CSR).
31.6.5 IrDA Mode
The USART features an IrDA mode supplying half-duplex point-to-point wireless communication. It embeds the
modulator and demodulator which allows a glueless connection to the infrared transceivers, as shown in Figure
31-23. The modulator and demodulator are compliant with the IrDA specification version 1.1 and support data
transfer speeds ranging from 2.4 kbit/s to 115.2 kbit/s.
The USART IrDA mode is enabled by setting the USART_MODE field in the Mode Register (US_MR) to the value
0x8. The IrDA Filter Register (US_IF) allows configuring the demodulator filter. The USART transmitter and
receiver operate in a normal asynchronous mode and all parameters are accessible. Note that the modulator and
the demodulator are activated.
Figure 31-23. Connection to IrDA Transceivers
The receiver and the transmitter must be enabled or disabled according to the direction of the transmission to be
managed.
To receive IrDA signals the following needs to be done:
 Disable TX and Enable RX
 Configure the TXD pin as PIO and set it as an output at 0 (to avoid LED emission). Disable the internal pull-
up (better for power consumption).
 Receive data
IrDA
Transceivers
RXD RX
TXD
TX
USART
Demodulator
Modulator
Receiver
Transmitter