ATEVK1105 Atmel, ATEVK1105 Datasheet - Page 326

• Manufacturer Part Number: ATEVK1105
• Description: KIT EVAL FOR AT32UC3A0
• Manufacturer: Atmel
• Series: AVR®32r
• Type: MCUr

Specifications of ATEVK1105

• Contents: Evaluation Board, Software and Documentation
• Processor To Be Evaluated: AT32UC3A0512
• Processor Series: AVR
• Data Bus Width: 32 bit
• Interface Type: USART, TWI, USB, SPI, Ethernet
• Operating Supply Voltage: 3.3 V
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Core Sub-architecture: AVR UC3
• Silicon Core Number: AT32UC3A0512
• Silicon Family Name: AVR
• Kit Contents: Board CD Docs
• Rohs Compliant: Yes
• For Use With/related Products: AT32UC3A0
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 26-28. Receiver Behavior when Operating with Hardware Handshaking
26.7.5
26.7.5.1
32058J–AVR32–04/11
RXBUFF
US_CR
Write
RXD
RTS
ISO7816 Mode
RXEN = 1
ISO7816 Mode Overview
Setting the USART to operate with hardware handshaking is performed by writing the MODE
field in the Mode Register (MR) to the value 0x2.
The USART behavior when hardware handshaking is enabled is the same as the behavior in
standard synchronous or asynchronous mode, except that the receiver drives the RTS pin as
described below and the level on the CTS pin modifies the behavior of the transmitter as
described below. Using this mode requires using the PDC channel for reception. The transmitter
can handle hardware handshaking in any case.
Figure 26-28 on page 326
The RTS pin is driven high if the receiver is disabled and if the status RXBUFF (Receive Buffer
Full) coming from the PDC channel is high. Normally, the remote device does not start transmit-
ting while its CTS pin (driven by RTS) is high. As soon as the Receiver is enabled, the RTS falls,
indicating to the remote device that it can start transmitting. Defining a new buffer to the PDC
clears the status bit RXBUFF and, as a result, asserts the pin RTS low.
Figure 26-29 on page 326
enabled. The CTS pin disables the transmitter. If a character is being processing, the transmitter
is disabled only after the completion of the current character and transmission of the next char-
acter happens as soon as the pin CTS falls.
Figure 26-29. Transmitter Behavior when Operating with Hardware Handshaking
The USART features an ISO7816-compatible operating mode. This mode permits interfacing
with smart cards and Security Access Modules (SAM) communicating through an ISO7816 link.
Both T = 0 and T = 1 protocols defined by the ISO7816 specification are supported.
Setting the USART in ISO7816 mode is performed by writing the MODE field in the Mode Regis-
ter (MR) to the value 0x4 for protocol T = 0 and to the value 0x5 for protocol T = 1.
The ISO7816 is a half duplex communication on only one bidirectional line. The baud rate is
determined by a division of the clock provided to the remote device (see
on page
The USART connects to a smart card as shown in
becomes bidirectional and the Baud Rate Generator feeds the ISO7816 clock on the CLK pin.
305).
CTS
TXD
shows how the receiver operates if hardware handshaking is enabled.
shows how the transmitter operates if hardware handshaking is
Figure 26-30 on page
RXDIS = 1
”Baud Rate Generator”
AT32UC3A
327. The TXD line
326