Atmel Xplained Pro Evaluation Kit for the ATSAMD21J18A Microcontroller ATSAMD21-XPRO ATSAMD21-XPRO Fiche De Données
Codes de produits
ATSAMD21-XPRO
436
Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181C–SAM-D21_Datasheet–07/2014
Figure 25-5. Connection with a Remote Device for Hardware Handshaking
Hardware handshaking is only available with the following configuration:
z
USART with internal clock (CTRLA.MODE = 1).
z
Asynchronous mode (CTRLA.CMODE = 0).
z
Flow control pinout (CTRLA.TXPO = 2).
The receiver drives its RTS pin high when disabled, or when the receive FIFO is full. This indicates to the remote device
that it must stop transmitting after the ongoing transmission is complete. Enabling and disabling the receiver by writing
RXEN will set/clear the RTS pin after a synchronization delay. When the receive FIFO goes full, RTS is immediately set
and the frame that is currently being received will be stored in the shift register until the receive FIFO is no longer full.
that it must stop transmitting after the ongoing transmission is complete. Enabling and disabling the receiver by writing
RXEN will set/clear the RTS pin after a synchronization delay. When the receive FIFO goes full, RTS is immediately set
and the frame that is currently being received will be stored in the shift register until the receive FIFO is no longer full.
Figure 25-6. Receiver Behavior when Operating with Hardware Handshaking
The current CTS level is available in the STATUS register (STATUS.CTS). Character transmission will only start if CTS is
low. When CTS goes high, the transmitter will stop transmitting after the ongoing transmission is complete.
low. When CTS goes high, the transmitter will stop transmitting after the ongoing transmission is complete.
Figure 25-7. Transmitter Behavior when Operating with Hardware Handshaking
25.6.3.3 IrDA Modulation and Demodulation
IrDA modulation and demodulation is available with the following configuration. When enabled, transmission and
reception is IrDA compliant up to 115.2 kb/s.
reception is IrDA compliant up to 115.2 kb/s.
z
IrDA encoding enabled (CTRLB.ENC=1).
z
Asynchronous mode (CTRLA.CMODE = 0).
z
16x sample rate (CTRLA.SAMPR[0] = 0).
During transmission, each low bit is transmitted as a high pulse with width as 3/16 of the baud rate period as illustrated in
.
RXD
CTS
RTS
USART
TXD
RTS
CTS
Remote
Device
TXD
RXD
RTS
Rx FIFO Full
RXD
RXEN
CTS
TXD